Islamabad ? Pakistani forces repelled a mass assault on their outpost near the Afghan border Saturday in a battle that left 18 dead and shook claims by Pakistan’s army to have regained control of a critical region.

A separate clash in the nearby Swat Valley piled pressure on a disputed peace deal there, while a Taliban commander suspected in attacks on trucks carrying supplies to NATO and U.S. troops in Afghanistan surrendered to authorities, officials said.

Under the peace deal, the government agreed to impose Islamic law in Swat and nearby areas to halt two years of bloody fighting. The controversial pact has been likened by the United States to surrender. It heralded a militant push into a neighboring district within 60 miles of Islamabad.