PESHAWAR, Pakistan (CNN) -- A suspected U.S. missile strike Thursday afternoon killed as many as four people in Pakistan's South Waziristan region and injured seven others, according to an intelligence official and witnesses in the tribal region.
Residents said they saw two unmanned planes flying over the Saam area in Wana, the capital of South Waziristan -- a region which the U.S. says is used by extremists as a staging ground to attack U.S. forces and their allies in Afghanistan.
The U.S. is the only country operating in the region known to have the capability to launch missiles from remotely-controlled drones.
Maj. John Redfield, a military spokesman for U.S. Forces Afghanistan in Kabul, had no comment about the reported strike.
One resident said the planes hit two houses in Saam, killing and wounding several people, including women and children. A Pakistani intelligence official in Wana confirmed the attack, and said four civilians were killed and seven wounded.
Pakistan's military is fighting Taliban and al Qaeda militants in the lawless tribal region along the border with Afghanistan. U.S. forces based in Afghanistan are suspected of attacking militants in Pakistan's tribal region, primarily through missile strikes carried out by unmanned drones.
Last month, the U.S. military reportedly sent ground forces into South Waziristan without Islamabad's permission, prompting an angry response from Islamabad over reported civilian casualties. And media reports have said that several months ago, President Bush authorized U.S. special forces to carry out ground assaults inside Pakistan without seeking Islamabad's permission.
CNN's Zein Basravi and journalist Janullah Hashimzada contributed to this report.