A missile fired from a drone killed four people, including a Yemeni fighter linked to al-Qaeda, when it hit their car in northern Pakistan on Saturday evening, intelligence and tribal sources said.
The strike at Sheen Warsak village in South Waziristan followed another drone attack in the same area two days earlier.
A Yemeni fighter called Abdul Rehman, allied to al-Qaeda, was among the dead, government and intelligence sources said.
It is difficult for journalists to verify the casualties from drone strikes since the government forbids foreign journalists from travelling to the area without a military escort and the Taliban often seal off the sites of strikes.
Many Pakistanis say the strikes are a violation of national sovereignty and that civilian casualties encourage families seeking revenge to join the insurgency.
But the U.S. says civilian deaths are minimal and the drones operatr in areas outside of Pakistani government control.