WASHINGTON — President Joe Biden on Friday vowed to halt crossings at the border when it’s “overwhelmed” if Congress passes bipartisan immigration legislation giving him that authority.

In a strongly worded statement, Biden threw his support behind an emerging immigration deal in the Senate, one that former President Donald Trump is seeking to torpedo since it could hand a legislative victory to his likely opponent in November.

“What’s been negotiated would — if passed into law — be the toughest and fairest set of reforms to secure the border we’ve ever had in our country,” Biden said Friday night. “It would give me, as President, a new emergency authority to shut down the border when it becomes overwhelmed. And if given that authority, I would use it the day I sign the bill into law.”

Biden, who has recently expressed optimism that a bipartisan deal could come soon, reiterated that the border is “broken” and argued that “it’s long past time to fix it.”

“Securing the border through these negotiations is a win for America. For everyone who is demanding tougher border control, this is the way to do it,” he said. “If you’re serious about the border crisis, pass a bipartisan bill and I will sign it.”

Congressional Republicans, particularly in the House, have said they will only accept aid money for Ukraine if it is coupled with tougher immigration policies.

The Biden administration made a supplemental request last year tying border funding to aid for Ukraine and Israel. Senate negotiators have recently ramped up talks to strike a deal on those issues, even as Trump has encouraged Republicans to reject a bipartisan border deal.

Biden’s statement on Friday comes as U.S. Customs and Border Protection released numbers showing encounters with undocumented migrants hit a new record in December by exceeding 300,000 — with most at the southwest border.

According to preliminary government data, the U.S. saw more than a 50% decrease in border encounters between ports of entry in the nation’s southwest during the first half of January.

“CBP’s message for anyone who is thinking of attempting to circumvent lawful pathways to enter the United States is simple: don’t do it,” said U.S. Customs and Border Protection in a statement. “When noncitizens cross the border unlawfully, they put their lives in peril.”

This article was originally published on NBCNews.com