Militants fired on security forces patrolling a restive area in southwestern Pakistan, triggering fierce fighting that left six troops and an unknown number of insurgents dead, the military said Monday. The clashes began late Saturday near Dera Bugti, a town in Baluchistan province at the center of a yearslong struggle between security forces and ethnic Baluch insurgents. Paramilitary forces who engaged and pursued the attackers stumbled on two training camps, where they recovered a large haul of arms and ammunition, military spokesman Lt. Col. Shahid Mehmood Khan said. Khan said the fighting killed six troops and "many" militants, but had no precise figure. Another nine troops were wounded before they withdrew on Monday morning. The military said the camps were used to prepare attacks on natural gas and plants and other installations in the region.