Four missiles struck a convoy of militants traveling by car and on foot near the town of Ghulam Khan in the North Waziristan tribal area along the Afghan border, the two officials said on condition of anonymity because they are not authorized to speak to the media.
Ghulam Khan is known to be dominated by fighters from a militant group headed by Maulvi Gul Bahadur.
It was the third day this week of missile attacks on the North Waziristan tribal region, part of a ramped-up U.S. campaign to take out al-Qaida and Taliban fighters seeking sanctuary outside Afghanistan.
More than 110 such missile strikes have been launched this year - more than double last year's total. Nearly all have hit North Waziristan, a region that hosts several militant groups battling U.S. and NATO troops in Afghanistan, including the feared Haqqani network.