ISLAMABAD, March 19: A Pakistan military spokesman on Friday said that nobody had seen senior Al Qaeda leader Dr Ayman Al Zawahiri in South Waziristan Agency , and assumptions about the presence of 'a high-value' target in Wana were based on the level of resistance that had been put up by 300 to 400 'hardened terrorists' during the operation.

Maj-Gen Shaukat Sultan, Director-General, Inter Services Public Relations, said at a media briefing on Wana at the GHQ that a 'couple of thousand' Pakistani troops were engaged in Wana and had cordoned off an area of 50 square kilometres.

Explaining the high casualties suffered by Pakistani paramilitary forces, the spokesman said the Frontier Constabulary underestimated the level of resistance and "barged into the den of hardened terrorists on March 16".

He said when the Frontier Constabulary started the search operation, it came under fire from trained terrorists. These hardened terrorists used the local population as human shield, and the Pakistani forces, in order to keep the collateral damage to the minimum, applied maximum restraint.

He said so far 30 to 35 insurgents, most of them foreigners, had died. Efforts are being made to determine their national identities. The military spokesman said the operation in Wana was still going on in which a 'couple of thousand' Pakistani troops armed with artillery and Cobra helicopters were going ahead against the targets.

When asked how long would the operation would continue, the spokesman said a timeframe for the operation had been fixed but he would not like to disclose it due to operational complications. The spokesman brushed aside reports that Dr Ayman Al Zawahiri had managed to break the cordon of Pakistan army and gone back to Afghanistan.

About the presence of Osama bin Laden, he said it was only a guess and there was no verifiable information. He said that an attempt had been made to break the cordon in which one terrorist died and nine others fled back into their dens, which had been surrounded.

In the area of Razmak, four people were apprehended on Friday. Of them, one is an Arab and the remaining are possibly locals. A huge cache of weapons had been recovered from them, he said.

He said the local people in Wana were sympathetic to these terrorists, and the government was trying to make them realize that the environment had changed. "If they want to live in the past, the government is left with no option but to use force and flush out the terrorists."

He said five tribal agencies were responding to the government initiative and olive trees were being transplanted in the areas of these agencies. The military spokesman said the operation had not been launched at the behest of any foreign country. It was a sovereign act of Pakistan government in line with its policy of wiping out terrorism, he added.

It was a coincidence, he said, that US Secretary of State Colin Powell visited Pakistan when the operation was on. Maj-Gen Sultan denied that American soldiers were taking part in the operation, but accepted that about a dozen American experts might be in Pakistan and helping in deciphering intelligence reports.

He asked the international media to appreciate Pakistan's efforts and avoid making unjustified criticism. "We have done enough, but the international media must understand our environment," he said.