Missiles fired by an unmanned US drone have killed at least 24 people in Pakistan's Kurram tribal region near the Afghan border, officials have said.
Local officials said the dead were local Taleban and that the toll may rise. Thirty others were injured.
Correspondents say this is the fifth drone attack on Pakistani territory since Barack Obama became US president.
Pakistan is critical of the tactic because, it says, civilians are often killed, fuelling support for militants.
The target of the missile attack on Thursday night was a training camp run by a local Taleban commander.
The camp in the Brijo area is located some 20km from Pakistan's border with Afghanistan.
Local officials told the BBC Urdu Service that a drone fired four missiles into the camp, a huge compound with five rooms which served as a weapons store, meeting place and lodging for the local Taleban.
It was being run by Commander Fazal Saeed, who was present, along with 57 others, during the missile attack. Officials said that the commander escaped unharmed.
Taleban guards said that some of those in the camp were hostages the Taleban were holding.
Pakistan is critical of the US drone tactic
Witnesses said people living in the area turned off their lights following the blasts to avoid being targeted by missiles.
They said the entire Taleban compound was set on fire and that announcements were made using mosque loudspeakers in the area urging people not to approach the camp for fear of more drone attacks.
Last month, a missile strike in the same area targeted a suspected Taleban training facility.
Missile strikes by unmanned drone spy aircraft have mostly targeted foreign fighters in the Waziristan region over the past couple of years.
The BBC's Ilyas Khan in Islamabad says the strikes are now also targeting facilities run by local or Afghan Taleban in the lower Kurram region, from where attacks have been launched into the Khost and Paktia provinces of Afghanistan.
The southern parts of the lower Kurram region share borders with Afghanistan's Khost province, where US and coalition forces have major deployments of forces.
The US does not confirm drone attacks but no other countries have the power to deploy such weapons in the region.