Air strikes and ground clashes between Pakistani troops and armed groups in the northwest have left three soldiers and 34 fighters dead, the military has said.
The army operation centred on the village of Datta Khel in the North Waziristan tribal district, where the military has been mounting an offensive against armed group strongholds since June.
"During a search operation seven terrorists were killed in Datta Khel. Three soldiers including an officer also embraced martyrdom," a military statement said on Sunday.
Four soldiers were wounded in an exchange of fire, it added.
A security official also confirmed the incident but told the AFP news agency that the number of troops wounded in the attack was higher, estimating at least 11 soldiers had been injured.
Ahmadullah Ahmadi, a spokesman for Hafiz Gul Bahadur, the leader of a faction of Tehreek-e-Taliban Pakistan (TTP), claimed responsibility for the deaths.
Bahadur is reportedly unhappy with the military offensive in North Waziristan.
|Pakistan airstrikes have hit targets in the northwest
"We carried out this attack because the army has established new check posts here," Ahmadi told the AFP news agency in a telephone call.
A separate military statement said Pakistani jets bombed hideouts of armed groups in Datta Khel on Sunday, killing 27 fighters.
"In precise aerial strikes, 27 terrorists including some of their important commanders and foreigners were killed in Datta Khel," it said.
Security officials have described the village as a stronghold of armed groups. It is 40km west of Miranshah, the main town in North Waziristan.
Pakistan's semi-autonomous areas have long been a hideout for armed groups of all stripes - including al-Qaeda and the homegrown TTP - as well as foreign fighters such as Uzbeks and Uighurs.
It was not possible to independently verify the casualties as media are banned from the area.