The restrictions outside Delaney Hall immigration detention center were imposed after demonstrators who were protesting the conditions at the facility had clashed with the police.

© Vincent Alban for The New York Times

Homeland Security Secretary Markwayne Mullin’s proposal could block hubs like Boston, New York and Los Angeles from accepting international flights.

© Doug Mills/The New York Times

The methodically planned strategy is intended to pressure noncitizens, including many with legal status, to leave the United States.

© Salwan Georges for The New York Times

Dong Guangping, 68, fled China at least three other times but was always sent back. His friends hope things might be different this time.