At least two missiles struck the house, which was near Wana, the main town in the South Waziristan tribal area.
Authorities were trying to establish the identities of those killed, informed the officials to foreign news agency.
The U.S. has relied heavily on its covert missile campaign to take out al-Qaida and Taliban targets in the tribal areas. The vast majority of the missile strikes have focused on North Waziristan, home to several militant networks bent on attacking inside Afghanistan.
