U.S. officials say immigration authorities have taken 121 people into custody since Friday, in the first raids targeting the deportation of families who have entered the United States illegally since May 2014.
Homeland Security Chief Jeh Johnson said the detainees were taken into custody in the states of Texas, Georgia and North Carolina. He described them as members of Central American families who crossed into U.S. territory from Mexico.
Authorities said the detainees already had been ordered removed by an immigration court, after they had exhausted legal means to avoid being sent to their homelands.
Johnson said most were placed in family detention centers in Texas to await deportation.
The White House did not comment on specifics of the apprehensions, which have divided U.S. political leaders and stoked controversy with the American public. But spokesman Josh Earnest said immigration enforcement priorities are focused on deporting felons as opposed to families, while targeting recent border-crossers.
The latest detentions impact only a small fraction of some 100,000 Central Americans — most of them mothers or unaccompanied children — who began crossing the U.S. border in waves nearly 20 months ago.
Analysts have linked the surge to sharp rises in gang-related violence in Central America, as well as to efforts by people seeking to reunite with family members already in the United States.
The American Civil Liberties Union has condemned the deportations, which were first publicized in late December. An ACLU statement accuses federal officials of targeting families, and using the detentions as a "scare tactic to deter other families fleeing violence in Central America from coming to the United States."