After fighting raged through the night, dawn on Saturday saw jets screaming through the skies and helicopters hovering above the Shakai area of South Waziristan, some 400km southwest of Islamabad, said residents.
Up to 600 foreign fighters - including Arabs, Chechens and Uzbeks - are believed to be hiding in Pakistan's lawless tribal region, protected by local tribesmen.
The fighting has spread into neighbouring North Waziristan agency, where armed men fired rockets at paramilitary checkpoints during the night and soldiers returned fire, residents said.
The army killed 35 fighters and lost 15 of its men in fighting on Wednesday and Thursday, military spokesman Major-General Shaukat Sultan said on Friday. Three civilians have also been reported killed.
Pakistani tribesmen are said to
be protecting foreign fighters
Air force jets were sent in for the first time this week to bomb houses where fighters were suspected to have been hiding.
They also targeted a suspected training camp and al-Qaida safe house, said Sultan.
Meanwhile, a bomb exploded at the house of a senior paramilitary official in Dera Ismail Khan town, 130km east of the heart of the battles around Wana. A man was killed and four wounded.
Nobody immediately claimed responsibility for the blast and it was not immediately clear whether the offical was at home when it occurred. Police said he was not among the injured.