PESHAWAR, Pakistan — Three U.S. missile strikes hours apart killed 18 people in a militant stronghold near the Afghan border in northwest Pakistan on Saturday, two Pakistani intelligence officials said.

At least nine people were killed in the first strike when missiles destroyed a moving vehicle in the North Waziristan tribal region, the officials said.

Two hours later drones fired more missiles that struck people who had gathered to retrieve the bodies, killing five. A third strike Saturday evening once again targeted a moving vehicle in the Mohammed Khel area of North Waziristan, killing four people, they said.

The identities and nationalities of the 18 slain men were not immediately known, the officials said.