U.S. immigration officials may deport migrants to countries other than their home nations with as little as six hours' notice, a top Trump administration official said in a memo, offering a preview of how deportations could ramp up.

U.S. Immigration and Customs Enforcement will generally wait at least 24 hours to deport someone after informing them of their removal to a so-called third country, according to a memo dated Wednesday, from the agency's acting director, Todd Lyons.

ICE could remove them, however, to a third country with as little as six hours' notice "in exigent circumstances," said the memo, as long as the person has been provided the chance to speak with an attorney.