During the presidential campaign, Mr. Biden has said he would move quickly to undo the tougher restrictions on asylum enacted by the Trump administration, which disqualified people who did not seek protection on their way to the United States and forced asylum seekers to wait in Mexico.

On his first day in office, Mr. Biden plans to ask Congress for a broad overhaul of immigration laws. That proposal, which will be unveiled on Wednesday, includes a path to citizenship for 11 million undocumented immigrants now living in the United States, aid for damaged Central American economies and plans to help people fleeing violence.

Last month, Mr. Biden, in an effort to avert a rush for the border, cautioned that changes to immigration policy could not be put in place immediately after he takes office and that his administration would need “probably the next six months” to develop a more “humane policy” for processing migrants.