(Reuters) - A U.S. drone strike in eastern Afghanistan killed four Pakistani Taliban members and seven other insurgents, a district government official said Wednesday.

The drone's missiles killed the militants on Tuesday afternoon as members of the Pakistani Taliban were attacking a school in the Pakistani city of Peshawar, near the Afghan border, said Mahlem Mashuq, the governor of Sherzad district in Nangarhar province.

"Based on our findings, 11 insurgents, four of them Pakistani Taliban, were traveling in a pickup truck that was hit by a drone strike, killing all of them," Mashuq said.

The Pakistani and Afghan branches of the hard-line Islamist Taliban are loosely allied and operate across the porous border between the countries.

Both are dedicated to overthrowing their countries' governments and establishing rule by their strict interpretation of Islamic law.

The Afghan Taliban, however, issued a statement condemning Tuesday's Pakistani Taliban attack on the school in Peshawar that killed 141 people.