In a recent notice sent to Congress, the administration said it intended to take $20 million in foreign assistance funds and use it to help Mexico pay plane and bus fare to deport as many as 17,000 people who are in that country illegally.

The money will help increase deportations of Central Americans, many of whom pass through Mexico to get to the American border. Any unauthorized immigrant in Mexico who is a known or suspected terrorist will also be deported under the program, according to the notification, although such people are few in number.

Katie Waldman, a spokeswoman for the Department of Homeland Security, said the program was intended to help relieve immigration flows at the United States border with Mexico.