Pakistan's security forces have missed the opportunity to capture al-Qaeda's second-in-command, Ayman al-Zawahiri, a senior government official has said.

Rehman Malik, the adviser to Pakistan's prime minister on security affairs, said on Monday they also received a report al-Zawahiri's wife had been in the tribal region of Mohmand.

Pakistani forces stormed the location but did not find the couple, he said, without indicating when the raid took place.

"We certainly had traced him at one place, but we missed the chance. So he's moving in Mohmand and, of course, sometimes in Kunar, mostly in Kunar and Paktia."

Al-Zawahiri and Osama bin Laden, Al-Qaeda's leader, have been in hiding since the September 11, 2001, attacks on the United States.

They are both believed to be in tribal region that straddles northwest Pakistan and eastern Afghanistan.

According to Malik, three weeks of fighting in the Pakistani-Afghan border district of Bajur had killed a number of civilians and badly damaged several villages.

Al Jazeera's correspondent in Islamabad quoted a tribal and security sources as saying 15 Pakistani civilians were killed in tribal area of Bajaur when two shells fell on their two homes.

Of about 500,000 people who fled, many of them to government relief camps, about 30,000 had returned by Monday.

Hand in glove

Malik said the Pakistani Taliban were working directly with Al-Qaeda, providing them with shelter and acting as their mouthpiece.

"They have not only connections, I would say Tehrik-e-Taliban is an extension of Al-Qaeda," he said, referring to a Pakistani Taliban umbrella group which authorities blame for a string of bomb attacks over the past year that have killed hundreds of people.

Pakistan last month banned the Taliban group, which was also accused of the assassination of Benazir Bhutto, the former prime minister, in December.

The US says Al-Qaeda and Taliban fighters are based in sanctuaries in Pakistan's tribal areas where they orchestrate attacks in Afghanistan and Pakistan and plot
violent attacks in the West.

The resignation of Pervez Musharraf, the former president and staunch US ally, last month raised questions about the government's commitment to the unpopular US-led "war on terror" campaign.

But US Admiral Mike Mullen, chairman of the US armed forces, said last week he was encouraged by recent Pakistani action against fighters, while adding both Pakistan
and the United States needed to do more to shore up security.