A gun battle raged for more than two hours near Miranshah, the main town in the notorious militant stronghold of North Waziristan, tribal police official Taj Mohammed told AFP.
During the fighting a shell landed on a mosque near Miranshah, killing three civilians and wounding 15, a security official in the town said.
Security officials confirmed the clash while witnesses said helicopters were seen circling overhead.
The convoy came under attack from about a dozen militants armed with rockets and automatic rifles, officials said, and followed a US drone strike on a militant compound in North Waziristan on Saturday in which at least 10 insurgents were killed.
The Pakistani military said in a statement that nine security forces were killed in the fighting and "heavy casualties" were inflicted on the militants, though the exact number was not known.
Waziristan lies in northwestern Pakistan`s semi-autonomous tribal belt which Washington considers the main hub for Taliban and Al-Qaeda to plot attacks on the West and in Afghanistan.
Pakistan says the drone strikes are counter-productive and undermine government efforts to separate tribes from militants, violate Pakistan`s sovereignty, kill civilians and fuel anti-US sentiment. (*)