An al Qaeda leader, identified as an Iraqi, was among up to 20 people killed in a US missile strike in northwest Pakistan.
The intelligence official identified the al Qaeda leader as Abu Akash.
"He is a mid-level al Qaeda man who was leading a high-profile life in Mir Wali," said the official, who declined to be identified, referring to the second biggest town in the North Waziristan region on the Afghan border.
Two missiles were fired by a pilotless "drone" aircraft into a house in Mir Ali, a major sanctuary for foreign Islamist militants, an intelligence official said.
A witness said the house was ablaze after the strike.
US drones have carried out about 15 such missile attacks on militant targets in lawless ethnic Pashtun tribal lands on the Pakistani side of the border with Afghanistan since the beginning of September.
US forces also launched a cross-border commando raid in September.
The strike came two days after Pakistan summoned the US
ambassador to protest against missile strikes and demand that they be stopped immediately.