Senate negotiators have agreed to empower the US to significantly restrict illegal migrant crossings at the southern border, according to sources familiar with the matter, a move aimed at ending the migrant surge that has overrun federal authorities over the past several months.

President Joe Biden has vowed to use the authority offered by the deal, embracing measures that are far more draconian than he’s previously considered in an area many voters perceive him as weaker than former President Donald Trump.

The Senate deal, which is expected to be unveiled as soon as next week, would also speed up the asylum process to consider cases within six months – compared with the current system, under which it could take up to 10 years for asylum seekers.

The details provide a new window into high-profile negotiations that have been going on for months – as Senate leaders hold out hope they can attach the deal to aid to Ukraine, Israel and Taiwan as domestic and international crises loom. The plan would also put pressure on Republicans to decide whether to greenlight these new authorities or reject the plan as Trump has urged the GOP to defeat anything short of what he calls a “perfect” bill.

Biden, in a rare statement on ongoing congressional negotiations, said the deal that Senate negotiators have worked toward is both tough and fair.

“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,” he said in the statement Friday. “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.”

Under the soon-to-be-released package, the Department of Homeland Security would be granted new emergency authority to shut down the border if daily average migrant encounters reach 4,000 over a one-week span. If migrant crossings increase above 5,000 on average per day on a given week, DHS would be required to close the border to migrants crossing illegally not entering at ports of entry. Certain migrants would be allowed to stay if they prove to be fleeing torture or persecution in their countries.

Moreover, if crossings exceed 8,500 in a single day, DHS would be required to close the border to migrants illegally crossing the border. Under the proposal, any migrant who tries to cross the border twice while it is closed would be banned from entering the US for one year.

The goal of the trio of negotiators – GOP Sen. James Lankford of Oklahoma, Independent Sen. Kyrsten Sinema of Arizona and Democratic Sen. Chris Murphy of Connecticut – is to prevent surges that overwhelm federal authorities. The Biden administration and Senate leaders have been heavily involved in the talks, and more details of the deal are expected to be released in the coming days.

In December alone, there were over 300,000 migrant encounters. The source said if the new legislation were in effect, the border would be shut down now to illegal migrants. Another source familiar with the matter said that certain migrants would be allowed to stay if they show they are fleeing persecution — and that there would still be a minimum of 1,400 asylum applications that could be processed though legal ports of entry while the emergency authorities are in effect.

But the push to release a deal comes as Trump has rallied Republicans to reject any immigration compromise as he campaigns against Biden’s handling of the border. But a number of top Senate Republicans, including Mitch McConnell, say that the issue must be dealt with now since Democrats are willing to approve tougher restrictions.

This headline and story have been updated with additional reporting.

CNN’s Betsy Klein contributed to this report.