The Pentagon on Wednesday scuttled a plan offered by Poland to send its MiG-29 jet fighters to a U.S. air base in Germany for their later transfer to Ukraine.

The U.S. military cited concerns that Russian President Vladimir Putin could use the move as a pretext to escalate the war.

Warsaw said it would provide the aircraft to Ukraine, now in the second week of its war against Russia, if the U.S. would make up the loss with a complement of F-16 fighters.

But the Defense Department said Ukraine needs weapons to knock out enemy tanks and aircraft more than Poland’s hand-me-down MiG-29s.

“We believe the best way to support Ukrainian defense is by providing them with the weapons and the systems they need most to defeat Russian aggression,” chief Pentagon spokesman John Kirby said, shortly after Secretary of Defense Lloyd Austin spoke with his Polish counterpart.

The anti-armor and air defense weapons still flowing into Ukraine are being used with “great effect” to slow the Russian advance in the north and to degrade Moscow’s ability to control the airspace.

Ukraine still has several squadrons of mission-capable combat aircraft and adding Poland’s Soviet-era fighters to the inventory isn’t likely to make the Ukrainian air force more effective, Pentagon officials said.

The intelligence community has concluded that the Polish plan to transfer their MiG-29s to Ukraine through the U.S. might be mistaken in Moscow as “escalatory,” possibly triggering a Russian overreaction, Mr. Kirby said.

“There are alternative options that are much better suited to support the Ukrainian military in their fight against Russia. We will continue to pursue those options,” he said.

“We’re going to continue to talk to the Ukrainians about their needs and we’re going to continue to talk to our allies and partners about how to best fill those needs,” the spokesman said.

Sen. Tom Cotton, Arkansas Republican and a member of the Senate Armed Services Committee, ridiculed the Biden Administration for blocking Poland’s plan.

“It’s weakness, and the Administration’s rationale makes no sense. How are jets ‘escalatory’ when we are already sending Javelin missiles?” he wrote on Twitter.

“Sending jets for Ukrainians to use isn’t ‘escalatory.’ Putin’s decision to invade and bomb children’s hospitals is ‘escalatory,’” Mr. Cotton said.

The House approved legislation Wednesday night that would ban Russian energy imports, a move that came on the heels of President Biden issuing his own embargo via executive order.
 
The House bill to cease all imports of Russian oil, natural gas and coal received overwhelming bipartisan support, passing by a vote of 414-17.

Still, questions loomed over whether the Democratic-led Senate will consider the legislation amid hesitancy among some Democrats about stepping on Mr. Biden‘s toes.

The pressure from Congress over the past week to ban U.S. imports of Russian energy and stem the flow of money funding Moscow’s war machine in Ukraine ultimately forced Mr. Biden to take executive action on a ban Tuesday.

The step is expected to increase prices at the pump even more as the national average for unleaded gas breaks all-time highs each day. That number on Wednesday was at $4.25 per gallon, up nearly 60 cents from one week ago.

But despite the president’s unilateral move, many lawmakers expressed a willingness to pass their own legislation codifying Mr. Biden’s ban. The House measure goes several steps further than his executive action and would add some conditions around Mr. Biden lifting or altering the sanctions.

Democratic proponents argued the legislation would also strengthen the executive order against legal challenges and offer lawmakers a political victory for voters back home.

In addition to placing an embargo on all Russian energy products, the House measure would require the U.S. to seek Russia’s suspension from the World Trade Organization while barring Belarus from joining.

It would also subject the president’s restoring Russian imports to a congressional veto, and would reauthorize and strengthen legislation that makes it easier for the president to slap more sanctions on foreign leaders.

Should Mr. Biden seek to ease sanctions, Congress would have 90 days to block such action. The carve-out was an important one for some Democrats, particularly more far-left members, who worried that too many conditions would tie Mr. Biden’s hands amid a fluid foreign policy conflict.

But despite watering down the legislation, some Democrats questioned whether any congressional action was necessary.

“I don’t know that we need it,” said Rep. Pramila Jayapal, Washington Democrat and chair of the Progressive Caucus, who voted for the ban. “My biggest concern is making sure we preserve some options for [Mr. Biden] to take to stop this war.”

Between the White House and leaders in Congress, Democrats have been out of sync on a Russian energy ban.

House Speaker Nancy Pelosi, California Democrat, was quick with public calls for an embargo, while Mr. Biden and Senate Majority Leader Charles E. Schumer only eased their opposition in response to bipartisan pressure.

Mrs. Pelosi denied that the House moving forward with a ban in the wake of Mr. Biden‘s executive action would create tension between Democratic leaders on Capitol Hill and the White House.

“No, I think we’re all pretty good. We’re all pretty good. It’s all about time, and we’ve been talking about doing the Russian ban for a while, and we’re so pleased that the president has done that,” she told reporters. “We have strong bipartisan support for the legislation.”

Mr. Schumer has not committed to holding a vote on the House-passed ban.

“We first have to see what the House passes, and then we’ll discuss things with the administration and find the best way to make sure that the … oil import ban is tight and tough,” the New York Democrat told reporters this week.

Other Democratic senators and close allies of Mr. Biden expressed similar hesitation. Some offered blunt criticism.

“Maybe I’m misunderstanding. If the president [signs] an executive order, why is there a need to legislate in the House?” said Sen. Chris Coons, Connecticut Democrat and confidant to Mr. Biden. “Good for them, that’s great. God bless.”

Sen. Chris Murphy, Connecticut Democrat, similarly argued that Congress did not need to act.

“I think there’s some reason to give the administration flexibility here,” Mr. Murphy said. “They’ve done what Congress has asked. I’m not sure that it’s necessary to tie their hands.”

The danger of China conducting a major military attack on Taiwan has increased in the wake of the Russian invasion of Ukraine, senior military and defense officials told Congress on Wednesday.

The danger, based on China’s growing military power, is greater than at any time in recent years, Ely Ratner, assistant defense secretary for Indo-Pacific security affairs, told the House Armed Services Committee.

“I think there is a mounting threat of aggression from the PRC,” said Mr. Ratner, as U.S. officials assess Chinese President Xi Jinping is conducting a major buildup of military forces to prepare for an attack on Taiwan, which he has vowed to reclaim for the mainland.

“His capabilities are growing and his patience seems to be decreasing,” Mr. Ratner said.

The Pentagon is already working with Taiwan on one lesson from Ukraine — the need to develop stronger defense capabilities and the need for closer coordination with states in the region.

International unity in response to the Ukraine crisis is “an important signal to a potential aggressor in the Pacific,” Mr. Ratner said.

And while the threat of a Chinese invasion has increased since Russia‘s Feb. 24 invasion, punishing economic sanctions that have been imposed on the Kremlin for its aggression also could help deter China from attacking Taiwan, he added.

Adm. John Aquilino, commander of the Indo-Pacific Command, said the Russian invasion was “a real wake-up [call]” for the United States and Europe.

“No. 1, we have to look at this and say ‘Hey, this could happen,’” he said. “And I have a sense of urgency to execute the mission, as the secretary [of defense] has assigned, which is to prevent this conflict.”

To deter a Chinese attack, the Pentagon is building up forces and moving them closer to China, he said. A stronger U.S. military posture and greater efforts to assist Taiwan’s defenses are two key elements of the strategy.

Taiwan also is bolstering its reserve forces outside the uniformed armed services, forces that can provide fighting capabilities similar to the volunteers effectively battling Russians in Ukraine, he noted.

“I can’t tell you at this point what the PRC has learned from watching the European issue,” Adm. Aquilino said, using the acronym of People’s Republic of China.”

“What I would say is I think I’m seeing the right lessons that we’d like to learn,” he said. “No. 1, the investment of blood in order to prosecute this illegal event. Second, the international condemnation and the unwillingness to accept it. And third, the drastic economic impacts to the people. Those are the right lessons should this switch over to the Indo-Pacific region.”

House Armed Services Committee Chairman Adam Smith said recent belligerent statements about Taiwan from the Chinese government are “very, very dangerous.”

“We could easily see a China–Taiwan situation in the same way we now see Russia-Ukraine situation,” the Washington state Democrat said.

Chinese Foreign Minister Wang Yi said earlier this week that efforts by the United States to promote Taiwan‘s independence will “push Taiwan to a dangerous situation” and “bring unbearable consequences to the U.S. side.”

Adm. Aquilino said China is “increasing its aggression” toward Taiwan and other states, citing a recent border clash with India, a security crackdown in Hong Kong and the jailing of 1 million mostly Muslim residents of Xinjiang in western China.

Taiwan also has recognized the need to bolster its defenses and recently purchased 100 U.S. Harpoon anti-ship missiles that may not be delivered until 2025.

“The focus there is we need to get them there quickly,” Adm. Aquilino said.

Asked about delays in getting weaponry to Taiwan to deter China, Mr. Ratner said, “We’re currently in the process of evaluating all tools and authorities possible to expedite the provision of the necessary asymmetric capabilities to Taiwan, precisely to reinforce the kind of deterrent you are talking about.”

In his prepared statement for the hearing, Adm. Aquilino said eventually retaking Taiwan remains a high priority for Beijing: “PLA forces have long exercised in areas around Taiwan, but the scale and sophistication of this training has drastically increased,” he stated.

But the admiral appeared to back off a warning made in a congressional hearing a year ago that China could be ready to move against Taiwan in less than six years. His predecessor at the Indo-Pacific Command, Adm. Philip Davidson, had said China could strike Taiwan by 2027.

Chinese military forces in 2021 stepped up coercive activities, including flights into Taiwan’s air defense zone and amphibious assault training near the island.

“While the PRC claims to still prefer a peaceful resolution of cross-strait differences, it has never relinquished use of force as an option,” the admiral said.

China also is continuing an alarming military build-up that includes advanced weapons and capabilities for land, sea, air, space and cyberspace warfare.

“The [People’s Liberation Army] is developing capabilities to project power outside of the PRC’s immediate periphery,” he said. “Xi Jinping has publicly directed the PLA to complete most elements of military modernization by 2027, and they continue to execute the most extensive military build-up since World War II.”

China‘s navy is currently the world’s largest with around 350 warships and submarines, including 130 major surface combat vessels. Beijing plans to have a fleet of 420 warships in the next three years.

China also recently deployed a new J-20 fighter that will add to the power of what the admiral called the largest aviation force in the Indo-Pacific region.

“In addition to an extensive arsenal of advanced ballistic missiles, the PLA Rocket Force is pursuing land-attack, supersonic cruise missiles and other advanced weapons,” he said.

Russia also has increased military operations in the Pacific as a result of the Ukraine conflict.

Before the Feb. 24 operation began, Russian forces in the Far East “pushed out 20 ships and submarines as we can count, they placed them in defensive positions,” Adm. Aquilino said. “They postured other forces to be able to defend their eastern flank. So we absolutely have seen a change and we continue to monitor those like we do every day.”

Sen. Angus King said Tuesday that Russian President Vladimir Putin’s invasion of Ukraine amounts to a “colossal intelligence failure” that overestimated the capability of his army and underestimated the resistance of the Ukrainian people.

Mr. King, Maine independent and a member of the Senate Select Committee on Intelligence, said Russia has “already lost this war” and Mr. Putin’s best bet is to “cut his losses.”

“He has got himself into this absolute debacle,” Mr. King said on MSNBC’s “Morning Joe.” “He is destroying two countries right now.”

Mr. King said he is not sure whether Mr. Putin sees an off-ramp, adding that is concerning.

“Right now I think Putin is the most dangerous man in world history because he’s trapped and he has nukes and part of their doctrine is the possibility of using them,” he said.

Two weeks into the invasion, Russian forces have failed to control any of Ukraine’s major cities including the capital, Kyiv, but made significant advances in southern Ukraine.

Civilians remain stuck, often without food, shelter or electricity, according to reports. More than 2 million Ukrainian refugees have spilled into neighboring countries.

Others, meanwhile, have struggled to get out. 

Mr. King said even if Mr. Putin captures control of more cities, it could be impossible for him to hold them over the long haul, given Ukrainian opposition.

“It looks like he has made one of the greatest mistakes he could make, which is to intimidate the people that are telling you supposedly the truth,” the senator said. “This is a colossal intelligence failure.

Sen. Angus King said Tuesday that people are willing to feel an even greater pinch at the pump as long as they know the financial hit will help the people of Ukraine.

“Nobody likes the high gas prices,” Mr. King, Maine independent, said on MSNBC’s “Morning Joe.” “But people are really committed to defending the country of Ukraine and making a contribution to do so.”

The Biden administration and lawmakers have been weighing whether to ban Russian oil in response to the invasion of Ukraine at a time when prices for regular gasoline in the U.S. have soared past $4 a gallon.

Responding to Russia’s invasion of Ukraine, the United States, the European Union and their allies have launched a series of economic sanctions against Russia that have, among other things, targeted oligarchs and the entire banking system.

Secretary of State Antony Blinken said Sunday the United States and European allies are exploring banning imports of Russian oil.

Top congressional lawmakers, meanwhile, announced Monday that they reached a bipartisan deal on legislation to ban Russian energy imports and suspend normal trade relations with Russia and Belarus for the unprovoked invasion of Ukraine.

Mr. King said this weekend in Maine that the most frequent comment he received from constituents was “why the hell are we buying Russian oil?” and that he was told “let’s stop buying Russian oil — even though that could well increase gas prices.”

The senator said he agreed with a colleague on Capitol Hill who made the case that paying a little bit more for gasoline — on a temporary basis — is not much of a price to pay given that the people of Ukraine are dying.

“We can’t sugarcoat the fact that there are not going to be impacts in this country [from the various] sanctions that are being applied — particularly on the energy side,” he said.

More than 2 million refugees from Ukraine have fled to neighboring countries in response to the Russian invasion, according to United Nations officials.

The latest tally comes well into the second week of the Russian invasion and follows previous efforts to evacuate Ukrainian civilians from the southern port city of Mariupol who were struggling amid the Russian attack.

Video posted Tuesday by Ukrainian officials showed buses with people moving along a snowy road from the eastern city of Sumy and yellow buses with a red cross on them in the southern port of Mariupol.

“The Ukrainian city of Sumy was given a green corridor, the first stage of evacuation began,” the Ukrainian state communications agency tweeted.

Hundreds of thousands of Ukrainians reportedly have been left with little food, and in many cases lack heat, water and electricity. 

People continued to try to flee embattled Ukrainian cities along these safe corridors.

Safa Msehli, a spokesperson for the U.N.’s International Organization for Migration, tweeted that 2 million have now left, including at least 100,000 people who are not Ukrainian.

Russian and Ukrainian delegations had agreed last week to a tentative cessation of fighting along “green” humanitarian corridors to facilitate civilian evacuations. 

But the Ukrainian Interior Ministry adviser Anton Gerashchenko said Sunday Russia was not honoring the agreement. Those discussions have continued.

Russian forces have not been able to control Kyiv, but have made advances in southern Ukraine.

Russia’s army is much bigger and has superior firepower. Nonetheless, Ukraine has inflicted heavy losses against the Russian forces.

President Volodymyr Zelenskyy of Ukraine also resurfaced late Monday night, according to The New York Times, releasing a brief video on his Facebook page from his office in Kyiv, saying he was not hiding.

“We used to say: Monday is a hard day,” he said. “There is a war in the country so every day is Monday, and now we are used to the fact that every day and every night are like that.”

• This story is based in part on wire reports