WASHINGTON (AP) — The Biden administration on Thursday said it would immediately begin turning away Cubans, Haitians and Nicaraguans who cross the US-Mexico border illegally, a major expansion of an existing effort to stop Venezuelans attempting to enter the US.

Instead, the administration will accept 30,000 people per month from the four nations for two years and offer the ability to legally work, as long as they come legally, have eligible sponsors and pass vetting and background checks. These four affected nations are among those for whom migrant border crossings have risen most sharply, with no easy way to quickly return migrants to their home countries.

It is a massive change to immigration rules, and it will stand even if the US Supreme Court ends a Trump-era public health law that allows American authorities to turn away asylum seekers.

The new policy could result in 360,000 people from these four nations lawfully entering the US in a year. But currently, far more people from those countries are attempting to cross into the US on foot. Migrants from those four countries were stopped 82,286 times in November alone.

The Biden administration has struggled to manage increasing numbers of migrants crossing the US-Mexico border and has been reluctant to take hard-line measures that would resemble those of the Trump administration. That’s resulted in a barrage of criticism from Republicans who say the Democratic president is ineffective on border security.

Biden was to address the border changes in a speech later Thursday. He will travel to El Paso, Texas, this weekend, his first trip to the southern border as president, before a planned trip to Mexico City to meet with North American leaders on Monday.

Mexico has agreed to accept up to 30,000 migrants per month from the four countries who attempt to walk or swim across the US-Mexico border, according to the White House.

Under Trump, the US required asylum seekers to wait across the border in Mexico. But massive delays in the immigration system created long delays, leading to fetid, dangerous camps over the border where migrants were forced to wait. That system was ended under the Biden era, and the migrants who are returned now will not be eligible for asylum.