A missile strike by a suspected US spy drone has hit a compound in a Pakistani tribal area bordering Afghanistan, killing four people, security officials say.
The incident in the district of North Waziristan, a known haunt of Taliban and al-Qaeda militants, was the latest in a string of attacks on Pakistani soil that have raised tensions between Islamabad and Washington.
The United States has stepped up attacks on militants in Pakistani territory since a new civilian government came to power in Islamabad in March, and the incidents have become an issue in the US presidential election.
Death toll from Friday's blast exceeds 60
Pakistani officials say the death toll from a suspected suicide attack during a gathering of tribal elders in north-west part of the country on Friday has risen to more than 60.
The bombing rocked the assembly of a jirga, or tribal council, of more than 1,000 members of the Alikhel tribe in the Orakzai semi-autonomous tribal region near the Afghan border.
The meeting had been discussing the issue of raising a traditional army, or lashkar, against Taliban militants operating in the area.
In recent weeks, tribesmen in the north-west have taken up arms to fight the Taleban alongside Pakistani troops.
Orakzai, near the main north-west city of Peshawar, has been relatively calm in recent months, but other parts of the north-west have seen sustained military operations by Pakistani troops against militants in the regions of Bajaur and Swat.
There has also been an upsurge in cross-border attacks against suspected militant targets in Pakistan by US forces in Afghanistan.
Pakistan says these are undermining its efforts in the "war on terror".
Roadside bomb kills schoolgirls
President Asif Ali Zardari, widower of the former prime minister Benazir Bhutto, who was killed in December, said the government was determined to rid society of terrorism.
His comments followed two earlier attacks in the country. In the worst violence, at least 10 people were killed, including four children, when a roadside bomb exploded close to a prison vehicle and a school bus in the Upper Dir district of North-West Frontier Province.
Those killed included four schoolgirls and several policemen and prisoners.
In the other attack, at least 13 people were wounded when a suicide bomber attacked police headquarters in the capital, Islamabad.
The blast wrecked the corner walls of a three-storey building housing an anti-terrorist squad in a high security zone on the outskirts of the city.
It occurred as Pakistan's newly appointed intelligence chief briefed lawmakers on the internal security threat for a second day in a special closed session of parliament.
Islamabad has been on high alert since 20 September in the wake of a suicide truck bomb that killed 55 people and destroyed the high profile Marriott Hotel in the city centre.