ISLAMABAD, Pakistan — An American drone strike killed a top Pakistani militant commander in a northwestern tribal region, security officials said Thursday. The death of the commander, Maulvi Nazir, was seen as a serious blow to Taliban fighters who attack United States and allied forces in neighboring Afghanistan.

The drone strike took place on Wednesday night and targeted Mr. Nazir’s vehicle in the Angoor Adda area in South Waziristan. Five other people were also killed, including one of his aides, officials said.

“He has been killed; it is confirmed,” said a senior Pakistani intelligence officer, who spoke on the condition of anonymity. “The vehicle he was traveling in was hit.”