Seven Pakistani soldiers have been killed and 16 wounded after militants armed with guns and rocket launchers ambushed their convoy in the northwest tribal belt, officials said on Friday.
Dozens of Islamist insurgents on Thursday attacked the troops in North Waziristan, part of the lawless tribal region bordering Afghanistan and a known sanctuary of the Taliban and other Al-Qaeda-linked militant groups.
In other unrest in the region, 16 militants were killed in army operations in Orakzai tribal district, while the mutilated bodies of four men accused of spying for the United States were found dumped by a road in the area.
Two officers were among the dead in the ambush in Dattakhel, a Taliban stronghold and recent target of US drone missile strikes, about 20 kilometres (10 miles) from North Waziristan's main town Miranshah.
"It was a pre-planned attack. Dozens of militants first fired several rockets and then used other weapons and guns," an intelligence official based in Miranshah said, adding that four military vehicles were destroyed.
A military statement said the convoy was on a routine mission from Miranshah to Dattakhel.
"In the ambush, seven soldiers embraced shahadat (martyrdom), including an officer and a junior commissioned officer, while 16 soldiers were injured," the statement said. Two of the wounded are in a critical condition.
Under US pressure, Pakistan has in the past year significantly increased operations against militants in its tribal belt, which Washington has called the most dangerous region on Earth and a global headquarters of Al-Qaeda.
The rugged tribal terrain became a stronghold for hundreds of extremists who fled neighbouring Afghanistan after the US-led invasion in late 2001.
North Waziristan neighbours South Waziristan, where Pakistan has been focusing its most ambitious military offensive yet against Taliban militants.