"Two Pakistani jets strafed bases run by commanders closely linked to Baitullah Mehsud in Makeen and Ladha, killing 12 to 15 militants and wounding another 17," an army statement said.
Pakistan Air Force fighters have been carrying out heavy air raids on major towns and on Taliban concentrations in South Waziristan as a softening of tactics before unleashing a major ground offensive targeted to get Mehsud and other high-value militants of Taliban and Al-Qaeda, dead or alive.
Five more suspected Taliban militants were shot dead by police in a mid-night raid on the outskirts of Karachi.
"Police surrounded the house where the militants were hiding and asked them to surrender," a spokesman of the city police said.
"The militants opened fire which was retaliated by the police in which five militants with suspected links to Baitullah were killed. But six others managed to escape," he said.
Police recovered huge quantities of arms and ammunitions, suicide jackets and explosives from the house. Later, the spokesman said, the militants were apparently plotting large scale suicide bombings in the city.
In other incidents, militants fired six rockets at a para-military fort in Wanna, the main town of South Waziristan, an official said.
The security forces in turn shelled Taliban positions near the town killing two militants and injuring three others.
The running skirmishes between Taliban and military came as army continued to move troops, tanks and heavy artillery in preparation for a confrontation, which experts say would be one of the biggest test for Pakistani security forces in decades.
Ranged against heavily armed troops would be an estimated 12,000-15,000 Taliban and Al-Qaeda militants equally well armed but masters of hit-and-run tactics, learned from years of bloody experience in Afghanistan.
Though the army has been moving reinforcements for weeks in-and-around Wanna, there is yet no clue when the D-day would come.
"We cannot give you a timing. But we are moving at the right speed," Pakistan Foreign Minister Shah Mahmoud Qureshi told mediapersons at Trieste in Italy, where he is attending a meeting on Afghanistan, Pakistan called on the sidelines of the G8 meeting.