Additional U.S. funding for Israel and Ukraine is stuck on Capitol Hill as senators argue whether to tie it to U.S. border security.
A procedural vote on the package is set for Wednesday, but negotiations haven't been smooth.
A classified briefing on the matter dissolved into a shouting match along partisan lines on Tuesday.
Republican senators vowed to oppose an additional aid package unless it includes major changes to U.S. border policy. Democrats want to address the issue separately and say the funding for Ukraine and Israel is simply too important to be derailed by continued infighting over immigration.
Democrats on Capitol Hill accused Republicans of effectively holding additional aid for Ukraine and Israel hostage in exchange for policy changes at the southern border with Mexico.
Senators recounted the heated debacle to reporters outside of the meeting.
"It was immediately hijacked by leader McConnell," said Senate Majority Leader Chuck Schumer. "Then, when I brought up the idea that they could do an amendment, and have the ability to get something done on the border, you know, they get stuck."
Sen. Kevin Cramer of North Dakota said some senators left the room.
"People got up and walked out because it's a waste of time," said Cramer. "They said this isn't worth it, this is a joke, you're not serious about this, I'm going — and I don't blame them.
Sen. Chris Murphy of Connecticut came out of the meeting and said, "We are about to abandon Ukraine," highlighting the increasingly serious situation with global impact.
The stalemate cast doubt on whether an aid package for Ukraine and Israel can pass this year.
The briefing to be held Wednesday gives lawmakers a chance to change their mind, or hold firm.
