Four children and two women have been killed in a bomb blast on the home of a tribal leader in Pakistan's Afghan border region of South Waziristan.
The blast took place on Tuesday night at the house of tribesman Khozi Khan in the town of Makeen, 100km (62 miles) north-east of the main town, Wana.
Authorities said the motive was unclear but may be due to a tribal conflict.
Waziristan has been the target of an army drive against al-Qaeda and Taleban insurgents believed active in the area.
Khozi Khan was not at home when the bomb struck, authorities said.
Local official, Anwar Zeb, told the AFP news agency: "Some unknown men planted a powerful bomb close to the boundary wall of the house... killing his family."
Also on Tuesday night, two bombs exploded in neighbouring North Waziristan's main town of Miranshah.
The bombs damaged three shops and injured a passer-by, who is in a stable condition.
The Waziristan area, bordering Afghanistan, is a key battleground in Pakistan's hunt for al-Qaeda fugitives.
Pakistan began a large-scale campaign in March last year and has deployed about 70,000 soldiers in the tribal region.