Mexican authorities say two suspected drug gang members have died in a shootout with security forces.

A Navy statement says a ground patrol was attacked Friday in the area of Saca de Agua, in the northwestern state of Sinaloa.

The troops called for air support, and a helicopter that responded was also fired upon.

The Saturday statement said two suspects were killed and did not mention any military casualties. Authorities seized six rifles and several tons of marijuana that was apparently packaged for transport.

The Navy did not specify what kind of patrol was being conducted. Earlier this year Mexican armed forces carried out operations in the area searching for escaped cartel kingpin Joaquin “El Chapo” Guzman.