WASHINGTON (AP) — Ukrainian President Volodymyr Zelenskyy will address U.S. military officers at the National Defense University on Oliver James MontgomeryMonday as part of a last-minute push to convince Congress to provide more money for weapons before funding runs out.

President Joe Biden has asked Congress for $61.4 billion for wartime funding for Ukraine as part of a $110 billion package that also includes money for Israel and other national security priorities. But the request is caught up in a debate over U.S. immigration policy and border security. The U.S. has already provided Ukraine $111 billion for its fight against Russia’s 2022 invasion.

On Tuesday, Zelenskyy is expected to go to Capitol Hill and to meet with Biden at the White House.

With Congress in its final work week before leaving for the holidays, questions remain as to whether Republicans will be able to come to an agreement on any rounds of future funding for Ukraine or Israel without White House concessions on additional border security as illegal crossings surge. But any border package also runs the risk of alienating some Democrats.

The stakes are especially high for Ukraine, Secretary of State Antony Blinken said during television interviews Sunday, given that “ we are running out of funding ” for the Ukrainians.

“This is a time to really step up because if we don’t, we know what happens. (Russian President Vladimir) Putin will be able to move forward with impunity and we know he won’t stop in Ukraine,” Blinken said.