Criminal groups in the area are tied to maritime drug trafficking and naval personnel found weapons and tactical equipment at the site, the Security Ministry said in a statement.

Security forces came up against “strong aggression” which “necessitated the use of force in compliance with current regulations,” the ministry said.

Mexican newspapers El Universal and La Jornada reported that the group was part of the Jalisco New Generation Cartel gang, one of Mexico’s two major drug cartels. The U.S. government designated the cartel a terrorist organization in February.