Officials in Pakistan say two missiles were fired from the unmanned U.S. aircraft. The attack killed two Arab militants and two of their local allies after they parked their vehicle near the house of militant commander Ainullah in the town of Wana in South Waziristan and were drinking water as they stood on the road.
The U.S. drone strikes were resumed in Pakistan in June after a six-month hiatus. At the same time, Pakistan launched a military operation in North Waziristan, with the army saying it has killed more than 1,000 militants so far.
On Sunday, the Pakistani air force said its airstrikes destroyed five insurgent hideouts, killing 15 militants.
In another skirmish, Pakistan said it killed six militants after they attacked a paramilitary checkpoint in the Khyber tribal district bordering Afghanistan. The checkpoint is a passage for NATO supplies to Afghanistan.
Some information for this report was provided by AP and AFP.