PESHAWAR, March 18: Thousands of troops backed by helicopter gunships and fighter jets launched on Thursday a massive operation in parts of South Waziristan amid reports that a senior Al Qaeda leader , possibly Osama bin Laden's close lieutenant Dr Ayman Al Zawahiri, might be holed up in one of the areas, official sources told Dawn.

At about the same time, President Pervez Musharraf told CNN in an interview that a 'high-value' Al Qaeda target had been surrounded near the border with Afghanistan.

"We feel that there may be a high-value target," he said. "I can't say who." News agencies reported that officials believed the surrounded figure is Ayman Al Zawahiri. President Musharraf said the ferociousness of the surrounded fighters indicated that they were protecting someone particularly significant.

The operation was launched in Shin Warsak, Zha Ghondai and Kaloosha villages to flush out suspected Al Qaeda militants, Taliban and their local protectors, officials said.

Inter Services Public Relations chief Maj-Gen Shaukat Sultan said he had no figures about casualties suffered by troops, but highly credible sources said that six soldiers were killed and as many wounded in the fighting.

Casualties among the militants were not known but one official source said this could be 'very high' given the fact that civilians in the area had been evacuated to safe locations.

Officials said that 7,000 regular troops of the Pakistan Army and paramilitary Frontier Corps were pressed into action backed up by Cobra helicopter gunships and F-7 fighter jets to capture or kill foreign militants and their local protectors.

"We are taking extra care to ensure that unconcerned people are not troubled. As for the militants; we had given them ample time to surrender peacefully or leave the area. They and their local protectors have brought this upon themselves. They asked for it," South Waziristan administrator Muhammad Azam Khan told Dawn on phone from Wana.

The area was cordoned off at around 0700 hours and residents in the entire stretch of operation were given three hours to evacuate to two designated places in an obvious effort to what an official described as separate the 'good from the bad'.

Locals in Wana said about 1,200 families had taken shelter in the dusty town to escape shelling in the embattled zone. "There is chaos and panic. It's been a hellish day with shells falling and guns booming all around," said a resident reached on phone.

Officials said the troops engaged the militants at 10am once the three-hour deadline given to civilians expired. Locals in Wana said a shell hit a house in Kazha Panga killing 13-year-old Din Muhammad and wounding 13 others, including three women and five children.

The bodies and the wounded were taken to a private hospital, they said. Officials said that troops mostly used heavy artillery and fired mortars and rockets on militants holed up in compounds.

"We believe that some foreign militants are still out there, probably making their last stand," Brig Shah said. But most militants had left Kaloosha after putting up a bloody resistance to paramilitary troops on Tuesday, he added.

In Kuth Kali, a small village near Karikot, militants believed to be foreigners were offering tough resistance, officials said. "Our guys on the field who have engaged them say militants don't seem to understand Pushto," said one senior official.

Troops were firing mortars into Kuth Kali till after midnight when this report was filed. "I can still hear explosions. I have lost my sleep," said Muhammad Dilawar, a resident in Karikot.

Officials said that fierce winds and cloudy weather prevented helicopters from taking full part in the operation. Fighter jets were usedonly to provide cover to ground troops, they added.

But while troops battled militants at four different locations, the major thrust of the operation was Shin Warsak, a relatively plain area surrounded by small hillocks with a population of about 10,000.

Dawn has learnt on good authority that one of the men who had broken through a paramilitary security cordon in what looked like a bulletproof double-cabin pick-up truck amid hails of bullets on Tuesday could be Ayman Al Zawahiri.

Sources said the truck, which had survived bullets, was later found abandoned after it had rammed into a wall. "He seems to have been wounded and appears to be holed up somewhere in that area," claimed two different sources. "It is Shin Warsak where troops are facing the stiffest resistance," said these sources.

One source familiar with the Tuesday's operation said the truck that had broken through the cordon was closely followed by two other speeding pick-ups. Both, however, were blown up by paramilitary troops with mortars and shells.

A credible source said the sheer number of foreign militants - between 500 and 600 - who had put up a big fight on Tuesday, had raised suspicions of the likely presence of a 'high-value target.'

Another source told Dawn that the Egyptian surgeon was believed to be hiding in Shin Warsak. A senior security official acknowledged his men in the field too had picked up the same intelligence but said it was still too early to say anything with certainty.

"There is this perception. Let's hope this is true. If he is there, nothing like it," said the official. He, however, thought that Ayman Al Zawahiri and his men, if they were there, would rather want to put up a last stand and die than give themselves up. "Unless, of course, they run out of ammunition," he added.

Officials said troops surrounding the area were not going into the villages due to darkness and fierce resistance by the suspected foreign militants holed up there.

"Our men have also picked up these reports from the field but I don't think this is true," one official said. Officials said the operation was likely to continue for the next couple of days.

"We are determined to finish this business as quickly as possible," said Brig Shah. "There will be no let-up until we have wiped out the militants and cleaned the entire area."

Haji Pazir adds from Miramshah: An army major and a soldier were killed when a convoy they were accompanying was ambushed in the Shawal area in the North Waziristan Agency.

Maj Waheed, company commander, and Musa Khan, a nursing orderly, died and three others were wounded when attacked by suspected militants near Dabar Miyami.

There was an exchange of fire that lasted for about two hours, officials said, adding both sides used heavy weapons. In another incident, two soldiers were injured when a military truck hit a landmine on the Mirali-Miramshah road. The injured were taken to the agency headquarters hospital in Miramshah.