At least 12 people, including suspected militants, have died in a missile attack on a house in a Pakistan village near the Afghan border, reports say.
South Waziristan is a stronghold of al-Qaeda and Taleban militants
The house in Kalosha village, in the troubled South Waziristan region, was destroyed, officials and residents say.
It is not clear where the attack was launched from, but residents said they suspected it was from Afghanistan where Nato troops are fighting the Taleban.
Last month, an al-Qaeda leader died in a similar attack in a nearby region.
Witnesses told the BBC three missiles landed in the area, two of them hitting the house at about 0200 (2100GMT Wednesday). The explosions were clearly heard in the district capital, Wana, some 10km east of the village.
"There was a huge explosion, driving people out of their houses," Abdullah, a resident of Wana, told the BBC by telephone.
"It is difficult to say where the missile came from, but we think it was fired from Afghan territory," he said.
Residents of Kalosha said some Arabs had been living in the house for two or three months. Arabs and other foreigners linked to al-Qaeda take shelter in the tribal region, as do the Taleban and their local supporters.
Local administration sources told the BBC there were at least four Arabs among the dead, two Turkmen, and two Pakistani militants, known locally as "Punjabi Taleban".
Three suspected militants, all of them foreigners, were injured in the attack and moved to an unknown location by the local Taleban, officials said.
Witnesses in Kalosha said the house was completely gutted. The bodies, dug out by local people who reached the scene within minutes of the attack, were burned beyond recognition. The local Taleban are reported to have buried them in Kalosha's graveyard.
It is still not known how many people were staying in the house. The number of dead may increase as rescuers search the rubble for more bodies.
In January, top al-Qaeda militant Abu Laith al-Libi was killed in the region by a missile strike which is believed to have been carried out by an unmanned US aircraft. The BBC's Barbara Plett in Islamabad says US forces have fired missiles at suspected militants in Pakistan's tribal belt several times in recent years.
But the US and Pakistan seldom confirm such strikes, as they are widely seen as a violation of Pakistani sovereignty, she adds.
Polls show that a vast majority of Pakistanis do not think their government should cooperate with the US in its so-called "war on terror", even though they acknowledge that Islamic militancy is a serious problem in the country.
South Waziristan, which is near Pakistan's border with Afghanistan, is viewed by Nato troops as a sanctuary for al-Qaeda and Taleban militants operating in Afghanistan.
Last year, a local Taleban commander ousted Central Asian militants and their local supporters from the area with the help of Pakistani troops.
But local residents say some Arab militants are still living in the area under the protection of local militants.