A federal marine agent with U.S. Customs and Border Protection was fatally shot while approaching a suspected smuggling boat off the coast of Puerto Rico on Thursday morning, officials said.
Three marine agents were shot at while they approached the vessel, and the agents returned fire at the suspects' boat, according to a statement from CBP.
The agents "suffered various gunshot injuries" in the shootout, which was about 14 miles off the coast of Cabo Rojo, and were airlifted to hospitals, according to the statement. One agent died, but the conditions of the other two were not clear.
One of the two people on the suspected smuggling vessel died at the scene and the other was arrested, Customs and Border Protection said.
Homeland Security Secretary Alejandro Mayorkas said at a congressional hearing Thursday that he was briefed on the shooting.
"The difficulty of this job cannot be compared to the difficulty that our front-line personnel face every day," Mayorkas said, alluding to his own role.
Later Thursday morning, another Marine Interdiction crew intercepted another vessel that had contraband and firearms, according to Customs and Border Protection. Both people on board -- two U.S. citizens -- were arrested, the agency said.
ABC News' Luke Barr contributed to this report.