PESHAWAR - Pakistani commandos have dropped into a Taliban stronghold in Swat valley , stepping up a punishing offensive against militants that has now displaced more than half a million people.
Frightened civilians have streamed out of three northwest districts ripped apart by fighting, with the UN refugee agency announcing that 501,496 stranded people had registered with authorities since May 2.
In response to the civilian upheaval Pakistan's President, Asif Ali Zardari, has appealed for global aid for those people displaced by the fighting.
"We're appealing to the world, myself and the (UN) secretary general... to draw attention on the human catastrophe that is taking place," Zardari told reporters on Tuesday after conferring with UN chief Ban Ki-moon.
"They (civilians) are losing their crops, they're losing their earnings, their livelihood and their homes, so we want the world to help us," he added.
News of Zardari's appeal comes as airborne troops opened a new front in Swat's northern mountains on Tuesday, the suspected stronghold of firebrand Taliban commander Maulana Fazlullah and his top aides who have been behind a nearly two-year uprising that has devastated the area.
"Today Pakistan army heli-borne troops have landed in the valley of Peochar and their mission is to conduct search-and-destroy operations," Major General Athar Abbas told a news conference.
Military officials said the troop landings, around 65 kilometres (40 miles) northwest of the main Swat town of Mingora, were the first such assault during the latest US-backed offensive to crush the Taliban in the district.