In his visit to Washington on Wednesday, Zelensky will ask Biden and US lawmakers for shipments of additional arms to Ukraine, including more sophisticated weapons, as some Republicans grow skeptical of continued American support.

His stop in the US capital is expected to be highlighted by a Biden administration announcement of plans to deliver Patriot air-defence missiles to Ukraine, a significant escalation of American support as Zelenskiy’s country endures a barrage of Russian missiles aimed at civilian infrastructure.

Plans for the Ukrainian leader’s trip were closely held and described by people familiar with the matter. They requested anonymity because his visit has not been publicly announced and his agenda could change because of security concerns. It would be Zelenskiy’s first trip outside Ukraine since Russia invaded on 24 February.

Zelensky’s address to Congress will take place as lawmakers put the final touches on a $1.7-trillion spending bill for Biden to sign in the coming days, with more than $45-billion to aid Ukraine. Yet as Republicans prepare to take control of the House in less than two weeks, prospects for future assistance have grown murky as some GOP lawmakers voice doubts about devoting more US resources to the war.

Representative Marjorie Taylor Greene, a conservative firebrand, typified that scepticism in a mocking tweet on Tuesday after news broke about Zelensky’s visit. 

“Of course the shadow president has to come to Congress and explain why he needs billions of American’s taxpayer dollars for the 51st state, Ukraine,” tweeted Greene, a Georgia Republican. “This is absurd. Put America First!!!”

Even so, most GOP veterans including Senate leader Mitch McConnell insist their party still favours US military aid for Ukraine. 

“Providing assistance for Ukrainians to defeat the Russians is the number-one priority for the United States right now, according to most Republicans,” McConnell said on Tuesday.

The current House GOP leader and likely next speaker, California Representative Kevin McCarthy, has said there will no longer be a “blank cheque” for Ukraine assistance, though he hasn’t joined calls from some in the party to cut back or eliminate the aid.

Read more: US finalising arms upgrade to Ukraine with Patriot missiles

House Speaker Nancy Pelosi sent a letter to other representatives on Tuesday urging them to be “physically present” at the Capitol on Wednesday. She did not say why, but the letter provoked rounds of speculation in Washington.

“We are ending a very special session of the 117th Congress with legislation that makes progress for the American people as well as support for our Democracy,” Pelosi said. “Please be present for a very special focus on Democracy Wednesday night.”

White House spokespeople declined to comment on Tuesday night, and Zelensky’s press office did not reply to requests for comment after business hours in Kyiv. News of the Ukrainian leader’s plan to visit the Capitol was reported earlier by Punchbowl.

Zelensky’s visit to Washington follows by a day Russian President Vladimir Putin’s travel to Belarus, one of his most important allies, seeding new doubts about Moscow’s strategy and intentions. Belarus allowed Russian forces to attack Ukraine from its territory but has not sent its own troops to aid Putin’s floundering invasion.

National Security Council spokesman John Kirby said on Tuesday that the US has no indication Belorussian forces are becoming actively involved in the conflict but that Minsk continues to enable Putin’s war effort.

Zelensky made a surprise visit to the embattled town of Bakhmut on Tuesday, where soldiers gave him a Ukrainian flag. Zelensky said he’d “pass it on” to Congress and Biden, in comments broadcast on the Freedom TV channel.

Read more: A million shells and more: Pentagon revs up Ukraine weapons aid

Zelensky addressed Congress by video link from Ukraine in March, shortly after Russia’s invasion. In that speech to a joint session of the US House and Senate, he implored lawmakers for immediate assistance and invoked parallels to the September 11 terrorist attacks and Pearl Harbour.

In remarks on Tuesday night in Ukraine, Zelensky said it was critical to obtain more assistance as the country enters winter.

“We will do everything possible and impossible, expected and unexpected, so that our heroes have everything they need to prevail,” he said. “This week is extremely important for Ukraine – in order to get through this winter and next year.”

While Ukraine has had unexpected success pushing back Moscow’s forces from its capital and the cities of Kharkiv and Kherson, exposing Putin’s military as far less proficient than once believed, the country has faced repeated Russian missile and drone strikes on civilian and critical energy infrastructure.

The attacks, which have caused power, heating and water cuts, are believed to be aimed at heightening the misery of ordinary Ukrainians, testing both their will to keep up the fight and support for the country in the US and Europe. Biden has called the missile strikes on civilian targets “barbaric”.

Kyiv Mayor Vitali Klitschko said damage caused by Russia’s bombardments is being fixed and water supplies are resuming in the city. BM/DM