Ukrainian President Volodymyr Zelenskyy is expected to travel to Washington on Wednesday to meet with U.S. President Joe Biden and address Congress, according to people familiar with the matter.

Zelenskyy’s visit would be his first trip outside his country since Russia invaded on Feb. 24. The speech will follow an expected move by the Biden administration to announce plans to deliver Patriot anti-aircraft missiles to Kyiv, ratcheting up U.S. support.

Biden will meet with Zelenskyy at the White House, according to people familiar with the planning.

The people asked not to be identified because the speech has not been publicly announced, and they cautioned the plans aren’t final because of security concerns.

House Speaker Nancy Pelosi sent a letter to other representatives on Tuesday urging them to be "physically present” Wednesday.

"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 immediately comment. Zelenskyy’s press office did not immediately reply to requests for comment after business hours in Kyiv.

Zelenskyy addressed Congress in March, shortly after Russia’s invasion, speaking to lawmakers by video link from Ukraine. In that address to the U.S. House and Senate, he implored lawmakers for immediate assistance and invoked parallels to the Sept. 11 terrorist attacks and Pearl Harbor.

Congress is poised by the end of the week to send a $1.7 trillion fiscal 2023 spending bill to Biden that includes more than $45 billion to aid Ukraine.

But given significant House Republican skepticism about the war effort, the aid package may be the most substantial one for Ukraine in the near future. Republicans take control of the House in January and have vowed to more closely scrutinize U.S. financial assistance to Ukraine.

The speech will provide an opportunity for Zelenskyy to appeal to them directly.

Zelenskyy, in an address on Tuesday night in Ukraine, 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.”

Ukraine is facing repeated Russian missile and drone strikes that have targeted civilians and critical energy infrastructure in the country, causing cuts to power and water supplies.

On Tuesday in the capital Kyiv, electricity output is 50% less than needed, Serhiy Kovalenko, CEO of energy supplier YASNO, which provides the city power said on Facebook. Almost 1.1 million citizens had power cut off Tuesday, he said.

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

Zelenskyy has also pressed the U.S. for more advanced weapons systems to fend off the barrage of Russian air attacks.

The U.S. is also poised to approve plans to send Patriot air and missile defense systems to Ukraine, pending final approval from Biden and U.S. Defense Secretary Lloyd Austin, two U.S. officials said last week.

Punchbowl News reported earlier that Zelenskyy was expected to visit the Capitol.