Pakistani officials say a U.S. drone strike has killed at least eight militants in the country's northwest near the border with Afghanistan.

Officials say one of the missiles hit a vehicle traveling in the Birmal area of the South Waziristan tribal region Tuesday. Among the dead were two senior commanders of a militant faction led by Maulvi Nazir. The faction supports the Taliban in Afghanistan but is not hostile to Pakistani authorities.

Security officials said the drone fired up to four missiles into the vehicle.

Earlier this year, U.S. President Barack Obama publicly acknowledged for the first time that the United States uses drone strikes against militants in Pakistan.

Mr. Obama defended the operations, which have greatly increased during his administration, saying they are used for “very precise, precision strikes” against al-Qaida.

The Washington-based New America Foundation says drone strikes in Pakistan have killed between 1,700 and 2,700 people in the past eight years.

Pakistan rejects the strikes as violations of its sovereignty.