By Zaffar Abbas BBC correspondent in Islamabad

The vast mountainous region remains out of bound for non-locals. Journalists have been barred from the area, and the main town of Wana looks like a military garrison.

Local residents are getting caught in the crossfire

The latest military offensive in which air force bombers and gunship helicopters pounded an alleged training camp of suspected al-Qaeda militants, has resulted in heavy casualties. And it has taken the conflict to an area that until now had remained relatively peaceful.

This was the third time in recent weeks that the military bombed suspected militant hideouts. It has given a new and a more serious dimension to the security operation within the country.

Until now, aerial bombing has never been used to crush an armed insurgency in the country.

No end in sight

The military may not have suffered any serious casualties in the latest offensive, largely because it used air power and long-range rockets. But since the present conflict began in March, scores of soldiers have been killed, including officers.

In some ways it suggests that the military's assessments about the fighting strength of the militants, and the risk to civilians, were wrong.

So what will be the outcome of this bloody conflict, which does not seem to have an immediate end? No-one seems to have an answer.

The military offensive had been part of the overall war against al-Qaeda.

The US-led forces have largely been operating across the border in Afghanistan, and Islamabad admits, have also been assisting the Pakistani troops in surveillance and communication.

The co-ordinated effort is largely aimed at capturing top al-Qaeda leaders Osama Bin Laden and Ayman al-Zawahri. The men, and many of their close associates, are widely believed to be hiding in and perhaps operating out of the area.

Tribal groups angry

Since the start of operation, the military authorities have firmly established that a large number of Uzbek, Chechen and Arab militants were in the area.

Battle-hardened tribesmen have taken the military action as an attack on their sovereignty, and have been putting up stiff resistance.

Most parts of the semi-autonomous tribal region have traditionally resisted the presence of foreign forces, including Pakistani troops.

It was in July 2002 that Pakistani troops, for the first time in 55 years, entered the Tirah Valley in Khyber tribal agency. Soon they were in Shawal valley of North Waziristan, and later in South Waziristan.

This was made possible after long negotiations with various tribes, who reluctantly agreed to allow the military's presence on the assurance that it would bring in funds and development work.

But once the military action started in South Waziristan a number of Waziri sub-tribes took it as an attempt to subjugate them.

Attempts to persuade them into handing over the foreign militants failed, and with an apparently mishandling by the authorities, the security campaign against suspected al-Qaeda militants turned into an undeclared war between the Pakistani military and the rebel tribesmen.

Some analysts say it is a no-win situation for the Pakistani troops. They cannot abandon the operation half-way, but are now having to use bombers and gunship helicopters against what was earlier described as a "handful of foreign militants and some local miscreants".

Relations between the authorities and local tribesmen have deteriorated to such an extent that the troops may remain bogged down long after all the foreign militants have been eliminated or flushed out of the region.