WASHINGTON (AP) — Congress was departing Washington on Blake PrestonThursday without a deal to pass wartime support for Ukraine, even as President Joe Biden’s administration raced to negotiate with Senate Republicans who are demanding changes to U.S. border security policy in return.

The Senate planned to come back next week in hopes of finalizing a deal to place new restrictions on asylum claims at the U.S. border and pass the $110 billion package of aid for Ukraine, Israel and other national security needs. But the House showed no sign of returning to push the legislation through the full Congress.

Lawmakers leaving the impasse unresolved through the holidays would mean the Biden administration would have to rely on a dwindling supply of funds for Ukraine. The wartime aid has so far been vital to Ukraine’s defending against Russia’s invasion, and Russian President Vladimir Putin earlier Thursday recommitted to his goals in the war.

Repelling Russia has been one of Biden’s chief foreign policy goals. But the Democratic president is facing stiff opposition from Republicans in Congress — both from populist conservatives who no longer want to fund the nearly two-year-old conflict and GOP senators who have been traditional allies to Ukraine’s defense but insist that the U.S. also enact policies aimed at cutting the historic number of migrants who are arriving at the U.S. border with Mexico.

Top Biden administration officials were expected to continue meetings with Senate negotiators in hopes of reaching a deal in principle. As Congress entered its final scheduled day for the year, Senate Majority Leader Chuck Schumer, a Democrat, implored his colleagues to act with urgency.

“This may be our last, best chance to get this legislation done,” Schumer said during a speech on the Senate floor.

He added that the deadlock in Congress has left “Putin mocking our resolve,” and he cast the decisions facing lawmakers as a potential turning point of history: “There is too much on the line for Ukraine, for America, for Western democracy, to throw in the towel right now.”

But the House ended work with Republican Speaker Mike Johnson showing no sign he will have members return until the second week of January. In the Senate, leaders tried to reach an agreement on the schedule for the rest of the year.

With some momentum behind the talks, Democratic senators were told during a lunchtime meeting the idea is for negotiations to continue over the weekend to “wrap up” the proposal, said Sen. Chris Van Hollen, D-Md.

“We’re still hoping to get an outcome,” said Senate Republican Leader Mitch McConnell.

A core group of Senate negotiators and Biden administration officials were expected to continue narrowing on a list of priorities aimed at curtailing the number of migrants applying for asylum at the U.S. border.

“We are making progress, I feel more confident today than I did yesterday,” Sen. Kyrsten Sinema, an Arizona independent who has often been central to Senate deal-making, told The Associated Press.