A U.S. federal agent was killed and two were wounded in a gun battle with suspected drug smugglers on Thursday during an inspection of a vessel believed to be carrying drugs off the coast of Puerto Rico, U.S. officials said.

“These are brave members of our Air and Marine Operations within U.S. Customs and Border Protection,” said U.S. Homeland Security Secretary Alejandro Mayorkas in testimony before a U.S. Senate committee. …

The agents stopped the vessel, believed to be carrying controlled substances, 14 miles (22.5 km) off the coast of the Puerto Rican municipality of Cabo Rojo, CBP spokesperson Jeffrey Quinones told Reuters earlier.

Drug traffickers frequently use Puerto Rico, a U.S. territory, as an entrance point for narcotics being smuggled from the Caribbean to the continental United States.