Pakistani security officials say militants from neighboring Afghanistan have crossed the border and killed six Pakistani soldiers.

Authorities say the militants attacked Pakistani troops in the northwestern Upper Dir region on Sunday. Eleven of the attackers were killed in the ensuing clash.

Pakistan has protested similar attacks to Afghanistan, saying militants often cross into its territory and target troops. Afghan and U.S. officials, meanwhile, accuse Pakistan-based militants of carrying out attacks in neighboring Afghanistan and have repeatedly urged Pakistani leaders to crack down on militant safe havens in the country's northwest.

The Pakistani Taliban claimed responsibility for Sunday's attack in Upper Dir.