Trump administration officials on Monday blamed Mayor Eric Adams and New York City’s pro-immigrant laws for the shooting of an off-duty customs officer during an attempted robbery, and they warned that federal agents will flood the city in search of people who entered the United States illegally.

The 42-year-old officer was sitting with a friend in a Manhattan park late Saturday night when two men rode up on a scooter, police officials said. One of the men approached the officer and revealed a firearm, and when the officer realized he was being robbed, he drew his service weapon and the two men exchanged gunfire. Later that night, the police detained Miguel Francisco Mora Nunez, 21, who had come from the Dominican Republic in 2023, as a person of interest in the shooting.

On Monday, Kristi Noem, the U.S. homeland security secretary, said during a news conference in New York that a second person, Cristian Aybar Berroa, had been detained in connection with the attack. Ms. Noem said that both men were undocumented immigrants from the Dominican Republic, and police officials had said that Mr. Mora Nunez was wanted in connection with other violent crimes.

“When I look at what Mayor Adams has done to New York City, it breaks my heart to see the families that have suffered because of his policies,” Ms. Noem said. She accused Mr. Adams and mayors from other Democratic cities of “protecting criminals who go out and murder, rape, rob.”