WASHINGTON — His country's future at stake, Ukrainian President Volodymyr Zelenskyy used inspirational words, optimistic resolve and a nod to Christmas in appealing Tuesday to leaders in Congress for U.S. aid for his fighters in the war with Russia.

But after hours of talks on Capitol Hill, additional American support appeared in grave doubt as Zelenskyy arrived at the White House to huddle with President Joe Biden. The U.S. has already provided Ukraine $111 billion since Russian President Vladimir Putin launched his grinding invasion more than 21 months ago, but Republicans are insisting on linking any more money to strict U.S.-Mexico border security changes that Democrats decry.

The White House is warning that if new money isn't provided by year's end it will have swift consequences for Ukraine's capacity to hold its territory, let alone take back land captured by Russia.

Meeting with Zelenskyy in the Oval Office, Biden said, "Mr. President, I call on Congress to do the right thing, to stand with Ukraine, and to stand up for freedom." He added, "Congress needs to pass the supplemental funding for Ukraine before they break for the holiday recess. before they give Putin the greatest Christmas gift they could possibly give him."

Zelenskyy made his own case during his brief White House appearance with Biden and his private meetings with congressional leaders — that Ukrainian forces have fought fiercely to push back the Russian invasion with the help of American and other Western allies and it's no time for Ukraine's friends to step back.

"The fight we're in is a fight for freedom," Zelenskyy repeatedly said in the meetings on Capitol Hill, according to lawmakers.

Flanked by Democratic Majority Leader Chuck Schumer and Republican Minority Leader Mitch McConnell, Zelenskyy entered a private meeting with senators with a public bipartisan show of support and to some applause. But more than an hour later few senators' minds appeared changed.

Zelenskyy also visited the House leaders, including privately with new Speaker Mike Johnson, whose hard-right Republicans have been the most resistance to any deal. Johnson insisted afterward: "We do want to do the right thing here."

Zelenskyy sought to impress on the senators that Ukraine could win the war against Russia, telling them he was drafting men in their 30s and 40s in a show of strength for the battle. In his trademark olive drab, he stood before a portrait of George Washington, history hanging behind him.

To the House Democrats, he showcased his country's embrace of the West by pointing to the Christmas season, telling them it was the first year Ukraine would celebrate on Dec. 25 rather than the day Russians mark the holiday.

McConnell said Zelenskyy was "inspirational and determined" in the Senate meeting.

But Republican senators exited the meeting unmoved from their position. Sen. Markwayne Mullin of Oklahoma said the emergency funding wouldn't gain GOP support unless it includes "real, meaningful border reform."

Biden has been calling for a $110 billion U.S. aid package for Ukraine, Israel and other national security needs.

He has expressed a willingness to engage with the Republicans as migrant crossings have hit record highs along the U.S.-Mexico border, but Democrats in his own party oppose proposals for expedited deportations and strict asylum standards as a return to Trump-era hostility towards migrants. Homeland Security Secretary Alejandro Mayorkas headed to Capitol Hill to meet with negotiators as they try to reach a border deal,

One chief Republican negotiator, Sen. James Lankford of Oklahoma, said there was nothing Zelenskyy could say during his visit with the senators to sway the outcome.

"Hey, pay attention to us, but not your own country? No," Lankford told reporters.

Ahead of Zelenskyy's high-stakes meetings, the White House late Monday pointed to newly declassified intelligence that shows Ukraine has inflicted heavy losses on Russia in recent fighting along the Avdiivka-Novopavlivka axis — including 13,000 casualties and over 220 combat vehicle losses. The Ukrainian holdout in the country's partly-occupied east has been the center of some of the fiercest fighting in recent weeks.

U.S. intelligence officials have determined that the Russians think if they can achieve a military deadlock through the winter it will drain Western support for Ukraine and ultimately give Russia the advantage, despite the fact that Russians have sustained heavy losses and have been slowed by persistent shortages of trained personnel, munitions and equipment.

Russia has lost 87% of the military personnel it had before the Ukraine war, including contracted and other ground forces, naval infantry and airborne troops, according to a person familiar with a recently declassified intelligence analysis and granted anonymity to discuss it.

Additionally, of the 3,500 Russian tanks before the invasion, some 2,200 have been lost on the battlefield, the person said.

The result is forcing Russia to rely on Soviet-era weaponry and has set back efforts to modernize its ground forces, the person said the analysis shows.

It's Zelenskyy's third visit to Washington since the war broke out in February 2022, including a quick trip just a few months ago as aid was being considered. But his surprise arrival days before Christmas last December drew thunderous applause in Congress, his daring first wartime trip out of Ukraine.

At the time, lawmakers sported the blue-and-yellow colors of Ukraine, and Zelenskyy delivered a speech that drew on the parallels to World War II as he thanked Americans for their support.

But 2023 brought a new power center of hard-right Republicans, many aligned with Donald Trump, the former president who is now the GOP front-runner in the 2024 race for the White House.

Republican Rep. Michael McCaul of Texas, the chairman of the House Foreign Affairs Committee, said Zelenskyy might be able to take on the stalemate by showing the stakes of potential Russian expansion toward NATO, and making his case on "moral clarity and why is Ukraine important."

Zelenskyy kicked off the quick visit to Washington on Monday, warning in a speech at a defense university that Russia may be fighting in Ukraine but its "real target is freedom" in America and around the world.

Of the new $110 billion national security package, $61.4 billion would go toward Ukraine — with about half to the U.S. Defense Department to replenish weaponry it is supplying, and the other half for humanitarian assistance and to help the Ukrainian government function with emergency responders, public works and other operations.

The package includes another nearly $14 billion for Israel as it fights Hamas and $14 billion for U.S. border security. Additional funds would go for national security needs in the Asia-Pacific region.

As Biden and Zelenskyy met, the U.S. was preparing to announce another, relatively modest, million-dollar military aid package, according to U.S. officials.

The roughly $200 million in weapons and equipment will be taken from Pentagon stocks and include additional ammunition for the High Mobility Artillery Rocket Systems (HIMARS), high-speed anti-radiation missiles, anti-armor systems, artillery rounds, missiles, demolition munitions, 4 million rounds of small arms ammunition, generators and other equipment and spare parts, one official said.

Including that latest package, the U.S. now has about $4.4 billion remaining in weapons it can provide from department stockpiles.

Border security talks have focused on making it more difficult for migrants to claim asylum and releasing fewer of them temporarily into the U.S. while they await proceedings to determine if they can remain permanently.

As border talks drag, Biden's budget director said last week that the U.S. will run out of funding to send weapons and assistance to Ukraine by the end of the year.