Thousands of Pakistani troops backed by Cobra helicopter gunships targeted one suspected al-Qaida camp and two hideouts near Shakai valley in South Waziristan, military spokesman Major General Shaukat Sultan said on Friday.

At least five suspected fighters were killed, raising the death toll from three days of clashes to 58.

"We have retrieved five bodies of militants. Others are lying on the ground," Sultan told a news conference at army headquarters in Rawalpindi.

The ground and air offensive came a day after a top military commander survived an assassination attempt in the southern port city of Karachi when his convoy was ambushed by unidentified assailants.

Seven soldiers and three policemen were killed in the attack.

Chechen and Uzbek

Sultan said security forces estimated up to 50 foreign fighters
might have been in the area where the offensive was first launched.

Pakistan has captured several
suspected al-Qaida fighters

Some 300 to 400 al-Qaida-linked fighters - mainly Chechen and Uzbek but also including Arabs and Chinese Uighurs - are believed to be hiding in the region, he said. 

Residents in Wana said they heard gunfire and explosions until late Friday and earlier had heard the sound of helicopters.

Sultan said Friday's offensive was in response to Wednesday's deadly attack on Pakistani army posts, and gave an account of the killings he said were committed by the militants. 

He said the attackers killed nine paramilitary Frontier Corps
men and six regular soldiers.
   
The Pakistani government has accused "local facilitators" of derailing previous efforts to reach a non-military solution and said Wednesday's attacks on the army posts were an "abuse of the government's sincere offer" of amnesty. 

"The government was left with no choice but to respond in order to establish its writ and eliminate these foreign elements," a government statement said.