YANGON, Myanmar (AP) — Ethnic Rohingya militants in western Myanmar launched overnight attacks on more than two dozen police and border outposts, leaving 12 security personnel and 59 Rohingya dead, the government said Friday, in a dramatic escalation of fighting in the troubled region.

The office of the country's leader, Aung San Suu Kyi, said military and border police responded to the attacks by launching "clearance operations."

Police fought off groups of as many as 100 Rohingya attackers armed with guns, machetes and homemade grenades. The captured weapons were shown in photos posted onlin...