The Pakistan Army on Wednesday continued its offensive against pro-Taliban militants in the northwestern Swat valley, killing 40 ultras in fresh fighting as hundreds of people fled the troubled region.

The army said it had cleared a hub of resistance of militants from a prominent height near the road leading to Alpuri, the headquarters of Shangla district, which was recently taken over by the armed followers of radical cleric Maulana Fazlullah.

Military spokesman Maj Gen Waheed Arshad said some 40 militants were killed in this operation since Tuesday.

The troops are moving closer to Shangla and consolidating their positions and eliminating the militants before making a push towards Alpuri, officials said.

"We are concentrating on Shangla and evicting militants from there," Arshad said.

The Pro-Taliban militants continued to strike at the security forces in Swat, despite being pounded by gunship helicopters and artillery since the army assumed the lead role in recent operations.

At 6:30 am this morning, the militants fired 18 to 20 rockets at a camp of the security forces at Kabal near Mingora, the main town of Swat district, the army said, adding troops responded with retaliatory fire.

Hundreds of people also fled Swat valley after security forces asked them to leave the area to avoid casualties. Scores of vehicles have left the valley.

Some people who were too poor to afford the increased fares charged by transporters left the area on foot, making a dangerous trek through areas where clashes are continuing, local residents said.

The army has also launched relief operations for the displaced people.

Close to 300 people, a majority of them militants, have been killed in fighting between Fazlullah's men and security forces since late October, when the federal government rushed thousands of troops to quell the activities of the cleric known as 'FM Mullah' for his broadcasts from an illegal radio station.

Nine of Swat's 12 districts have been taken over by the militants, who have burnt down shops selling music CDs, forced women to wear burqas and banned girls from going to school.

After paramilitary forces and police were unsuccessful in tackling the militants, President Pervez Musharraf [Images] last week ordered the army to take a lead role in the operations. The army has amassed some 15,000 troops for an offensive against the militants.