(Bloomberg) -- Ukraine’s Volodymyr Zelenskiy is headed to Washington for talks with President Joe Biden and US congressional leaders, signaling a push to energize support among his country’s allies almost two years into Russia’s invasion.

With Biden’s request for further military assistance to Kyiv stalled in Congress, the Ukrainian president will make his case on Capitol Hill and at the White House on Tuesday at a key juncture in his fight to regain Russian-occupied territory.

“As Russia ramps up its missile and drone strikes against Ukraine, the leaders will discuss Ukraine’s urgent needs and the vital importance of the United States’ continued support at this critical moment,” White House spokeswoman Karine Jean-Pierre said in a statement Sunday. 

Zelenskiy is expected to make an in-person address to a meeting of all US senators on Tuesday morning, a Senate leadership aide said. House Speaker Mike Johnson will also meet the Ukrainian president, spokesman Raj Shah said on social media.

As Zelenskiy traveled to Washington, Russia targeted southern Ukraine with 18 drones and launched eight ballistic missiles at the Kyiv region in an attack lasting into the early hours of Monday. All were deflected, according to Ukraine’s air force. 

“We are using every day, every minute to give more to Ukraine, to our people — more opportunities, more protection, more strength,” Zelenskiy said in his daily video statement early Monday.

Continued US military support has hit a snag as senators struggle to reach a compromise on US-Mexico border policy changes that Republicans insist are needed for assistance to Ukraine to pass both houses of Congress. 

With lawmakers scheduled to leave Washington at the end of the week for the holiday break, Senate negotiators said Sunday that differences persist.

“Right now, Republican demands are unreasonable,” lead Democratic negotiator Senator Chris Murphy said on NBC’s Meet the Press. He said he expects the White House to get more engaged in the negotiations this week as negotiators try to resolve “some pretty big differences that remain.”

Republican negotiator Senator James Lankford said the Biden administration isn’t focused enough on tightening asylum rules. “They seem to be focused on how many people can we just release into the country and tell them we’ll do a hearing sometime later,” he said on CBS’s Face the Nation. 

Zelenskiy has said his country’s counteroffensive this year didn’t achieve its goals because allies failed to provide hoped-for weapons. A relentless ground war in eastern and southern Ukraine is heading into the winter as Zelenskiy deals with a troop shortage, uncertainty over military aid and divisions within the EU.

Zelenskiy will arrive in the US on Monday on a mission to secure unity among the US, Europe and the rest of the world in supporting Ukraine’s defense against Russia’s invasion, his office said in a statement.

Topics in Washington will include further US-Ukrainian defense cooperation, such as joint projects to produce weapons and air-defense systems, according to the statement.

Biden proposed almost $106 billion in emergency spending in October, including some $61 billion for a year’s worth of assistance to Ukraine — and $13.6 billion to secure the border. 

With the package in limbo in Congress, Biden’s budget director Shalanda Young said on Dec. 4 that the US would run out of resources to assist Ukraine by the end of the calendar year. “We are out of money — and nearly out of time,” she said in a letter to congressional leaders.

On Wednesday, Biden said he’s willing to make “significant compromises on the border” while accusing Republicans of holding funding for Ukraine hostage and putting US national security at risk.

Biden’s invitation to Zelenskiy underscores the US’s “unshakable” commitment to supporting Ukraine in its defense against Russia’s invasion, Jean-Pierre said Sunday.

Zelenskiy also expects to meet with IMF Managing Director Kristalina Georgieva in Washington, according to a person familiar with his plans. The IMF declined to comment. The fund’s executive board is expected on Monday to approve the latest disbursement of about $900 million on Ukraine’s $15.6 billion loan agreed in March.

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Before his Washington trip, Zelenskiy traveled thousands of miles to Argentina to try to persuade Hungarian Prime Minister Viktor Orban to drop his objections to the start of European Union accession talks with Ukraine. 

The two leaders talked for 10 to 15 minutes on Sunday on the sidelines of Argentinian President Javier Milei’s inauguration in Buenos Aires, according to a member of Ukrainian delegation. 

Orban is also blocking a €50 billion ($53.8 billion) EU aid package for Ukraine that’s set to be discussed during the Dec. 14-15 summit in Brussels.

“We spoke with maximum honesty, clearly, about our European affairs,” Zelenskiy said in his daily address.

Read more: Zelenskiy Urges Ukrainian Troops to Keep Initiative in Fighting

Zelenskiy also met with the leaders of Uruguay, Paraguay and Ecuador on his proposal for ending Russia’s invasion. He invited Paraguay and Ecuador to a meeting of national security advisers in January to implement his peace formula, a 10-point plan centering on the full withdrawal of Russian troops.  

“Support and a powerful voice of Latin America on the side of Ukrainian people in our fight for freedom and democracy are very important to us,” Zelenskiy told Ecuadorian President Daniel Noboa. 

--With assistance from Kateryna Chursina, Eric Martin and Erik Wasson.

(Updates with recent missile barrage in fifth paragraph, Zelenskiy’s comments in sixth, 21st)

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