Taliban militants armed with guns and rockets ambushed a Pakistani military convoy on Friday, killing seven soldiers in the militant stronghold of North Waziristan, officials said.
The attack took place at Khar Qamar, 30 kilometres (18 miles) west of Miranshah, the main town in the district that has become the most notorious Taliban and Al-Qaeda stronghold on Pakistan's border with Afghanistan.
The Pakistani security officials said nine militants were also killed in the attack, but there was no independent confirmation of the toll.
"At least seven soldiers were martyred when militants fired machine guns and rockets on a military convoy," a senior security official told.
Other security officials in Peshawar, the biggest city in northwest Pakistan, confirmed the attack and that the toll had risen from four to seven.
"After the ambush, Pakistani military helicopters and troops retaliated and there were reports of deaths of nine militants," an intelligence official said.
Pakistan has for years battled homegrown insurgents in the tribal belt on the Afghan border. It says more than 3,000 soldiers have died but has resisted US pressure to carry out a sweeping offensive in North Waziristan.
US and Afghan officials say Taliban use Pakistan's semi-autonomous tribal belt as a rear base in their 10-year insurgency against Kabul and US troops.