A US Central Command spokesman said the missiles were not fired by any military aircraft. This leaves open the possibility it could have been a pilotless drone aircraft which the CIA has used in Pakistan.

The intelligence official said four missiles were fired on Sunday at the house in Shahnawaz Kheil Dhoog, a village near the town of Wana in the South Waziristan region on the Afghan border, just after 3pm (6pm Singapore time).

'It was apparently an American plane that fired precision guided missiles at the house,' said the official, who asked not to be identified.

Three foreigners, an Arab and two Turkmen, were among those killed, according to the intelligence official.

Villagers put the death toll at 18.

'Except the boundary walls, the house has been destroyed,' said a senior district government official who declined to be identified.

'The place has been used for some time as a militant hideout,' he said.

The attack came a day after a Turkish woman was killed and five Americans were among 11 people wounded in a bomb attack at a restaurant popular with foreigners in the capital, Islamabad.

A spokesman for Pakistani Taleban militants claimed responsibility for the Islamabad bomb, the latest in a surge of attacks that began in July after troops stormed a radical mosque complex in Islamabad.

Hundreds of people, including former Prime Minister Benazir Bhutto, have been killed in bomb attacks since then, raising fears for stability in the nuclear-armed US ally.

US forces have used drones to fire missiles at militants on the Pakistani side of the border several times in recent years.

A missile believed fired by a US drone killed 13 suspected militants in South Waziristan in late February. On Jan 28, one of Osama bin Laden's top lieutenants, Abu Laith al-Libi, was killed in a strike in North Waziristan. -- REUTERS