Mexican authorities said Saturday that 17 gunmen were killed on Friday in a clash with members of the security forces in the northwestern state of Sinaloa.

Five municipal police officers were wounded in the clash, which began on Friday evening after the authorities received an emergency call that two men had been shot and killed outside a department store in the town of Villa Unión, about 15 miles southeast of the resort city of Mazatlán.

Local police officers encountered the convoy of gunmen on a rural road outside Villa Unión, and the groups exchanged gunfire, Cristóbal Castañeda Camarillo, the deputy secretary of public security in Sinaloa, said at a news conference on Saturday in the state capital, Culiacán.

The Sinaloa state police and soldiers of the Mexican Army were called in to support the local police, Mr. Castañeda said. After the shooting stopped, the authorities counted 17 dead. It was not clear if any of the gunmen had escaped.