'On the run'

The US says the militants in the area pose a direct threat to its security, and has demanded they be confronted.

An internally displaced girl holds a baby at a UNHCR (United Nations High Commission for Refugees) camp in Takht Bai, about 150 km (85 miles) northwest of Pakistan's capital Islamabad May 8, 2009. [Agencies]

In an interview during a visit to Washington, President Asif Ali Zardari confirmed on Friday that Pakistan wanted to "eliminate" the militants it is fighting.

Militant strongholds were hit from the air on Friday as troops conducted operations on the ground.

Pakistani military spokesman Gen Athar Abbas said troops had killed 143 rebels in Swat, 25 in Lower Dir and six in Buner, losing seven soldiers in Swat and three in Lower Dir.

Militants were "on the run and trying to block the exodus of civilians from the area", he said.

Earlier, he said that the military's objective was to eliminate some 4-5,000 militants from the Swat Valley and neighbouring districts of Dir and Buner.

The Pakistani military says it is trying to help displaced civilians by establishing camps where they can seek shelter.

But reports suggest many thousands of civilians under threat from the fighting are unwilling or unable to move.

Roads have been blocked or reportedly mined by the rebels.

The Pakistani military has also imposed an indefinite curfew over swathes of the region.

A local journalist in Mingora said that electricity and water had been shut down and markets had been closed since Thursday. There was, the journalist said, a real threat of food shortages in the coming days.

While the army accuses the Taleban of holding the people left in the Swat Valley hostage, those who have escaped blame both sides for the conflict and the dire position of the civilians caught between them, correspondents say.