The missiles hit a vehicle in the Spin Drand area of Khyber, the officials said, speaking on condition of anonymity because they were not authorized to talk to the media.
More than 100 missile strikes have hit Pakistan's border region this year. Nearly all hit targets in North Waziristan, a tribal area effectively under the control of Taliban and al-Qaida groups focused on battling U.S. and NATO troops across the border in Afghanistan.
Khyber is home to militant groups and has seen Pakistan army operations over the last two years. The main road used by trucks ferrying supplies to Western troops in Afghanistan crosses the region, which is not far from the main northwestern city of Peshawar.
The U.S. rarely acknowledges the covert CIA-run program and Pakistan officially protests the drone-fired missile strikes. But Islamabad is believed to secretly assist at least some of them.
In other violence Thursday, an assailant threw an explosive device at Shiite Muslims in an Ashoura mourning procession in Peshawar, wounding 16 people, two of them critically, said police officer Abdul Sattar. Authorities in Pakistan are on high alert for such attacks, which in the past have been carried out by Sunni extremists.
Anti-Shiite extremists in Pakistan predate al-Qaida and the Taliban, but these days the groups are connected.
Associated Press writer Riaz Khan in Peshawar contributed to this report.