Three paramilitary soldiers were killed when a group of militants launched a rocket attack on a mountain fort in Pakistan's troubled northwest early Sunday, security officials said.
The midnight attack took place in the Spinwam area of North Waziristan tribal district on the Afghan border, where the military launched a major offensive against the Taliban and other insurgents in June.
Officials said both military and paramilitary troops were inside the well-protected fort at the time.
"An unknown number of militants started firing rocket-propelled grenades from all sides. Three FC (Frontier Corps) men embraced martyrdom when one of the rockets landed inside the fort," an official in Peshawar said.
The attack was apparently staged in revenge for the ongoing military operation, he added.
An intelligence official confirmed the attack and the casualties.
Pakistan began a long-awaited push to clear insurgent bases from North Waziristan after a bloody raid on Karachi airport finally sank faltering peace talks with the rebels.
North Waziristan has become a major base for the Tehreek-e-Taliban Pakistan (Pakistani Taliban), which rose up against the state in 2007. The United States has long called for action in the area against militant groups targeting NATO forces in Afghanistan.
Pakistan's army says it has killed more than 900 militants and lost 82 soldiers since the start of the operation.