Democrats and Republicans will not be able to strike a deal on US southern border policy changes this year, GOP Sen. Lindsey Graham said Sunday, following weeks of negotiations over tying tighter immigration restrictions to supplemental funding for Ukraine and Israel.

Republicans, Graham said during an appearance on NBC’s “Meet the Press,” “feel that we’re being jammed. We’re not anywhere close to a deal. It’ll go into next year.”

Several congressional aides told CNN Sunday they are skeptical that Democrats and Republicans can reach an agreement on immigration reform, where sizable differences remain. Still, they report progress in the talks.

Democrats are pushing for a deal Sunday to have a Senate vote this week — a very ambitious deadline that many Republicans say is implausible.

If Congress leaves town for the holidays without reaching a deal, the White House will have to make tough choices about supplying allies such as Ukraine at the potential expense of US military readiness. Top Biden administration officials have been sounding the alarm for weeks about funding for Ukraine running dry and the potential consequences.

Graham said Sunday he was “willing to help Ukraine” and supports provisions in the supplemental funding package for Israel but made clear he would not approve any further aid until the border is secured.

While the White House has floated a number of concessions on border policy in an effort to reach a deal, a number of major sticking points remain. Among them is the possible elimination of humanitarian parole, a mechanism that allows migrants to temporarily live in the United States on a case-by-case basis.

For President Joe Biden, the politics of the moment are complicated. While losing support from the Democratic base could cost him at the polls next November, doing nothing on immigration could have broad and lasting implications as well. Over the past several weeks, the number of migrants apprehended at the border has spiked, which Republicans argue is a major liability for Biden and other Democrats heading into 2024.

“This is a catastrophe, and it’s a result of the Biden open border policies,” Sen. John Cornyn of Texas said on Fox News Sunday. “We’re going to use this opportunity to change that.”

Others on Capitol Hill have signaled more optimism about the direction of the negotiations, even if a deal isn’t struck this year. Democratic Sen. Joe Manchin of West Virginia said Sunday he is “very encouraged” by the status of the talks.

“I’ve been communicating with the negotiators, my colleagues and friends on the Democrat and Republican side, also with the White House too, and I’m very encouraged. I’m very optimistic they’re moving in a very positive way,” Manchin told CNN’s Jake Tapper on “State of the Union.”

“I know the House has been resistant, but I can assure you the House will not get anything accomplished unless they start working together in a bipartisan way on these very, very troubling and challenging pieces of legislation,” Manchin said.

This story has been updated with additional information.

CNN’s Manu Raja contributed to this report.

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