Pakistan's army declared a "full-scale" offensive against Taliban insurgents holed up in the Swat valley today as warplanes pounded militant bunkers and caused thousands more residents to flee.
The fighting was concentrated in the main town, Mingora, where the bulk of an estimated 4,000 Taliban fighters across Swat are heavily dug in. Artillery and helicopter gunships battered militant-held buildings, while the Taliban planted mines across the city in expectation of a major ground offensive.
At military headquarters in Rawalpindi, Major General Athar Abbas said the mission was to "eliminate" the militants from Swat, a former tourist haven where the army assault has become a test of Pakistan's commitment to rolling back Islamist militancy in North West Frontier province.
Abbas said troops had killed 143 militants in Swat over the preceding 24 hours, and 16 in smaller battles in neighbouring Dir and Buner districts. He gave no details of civilian casualties but testimony from thousands of people fleeing the area suggested dozens of deaths and injuries.
UN officials repeated warnings that the flood of people was swelling into one of the world's largest humanitarian crises. In Mingora, long traffic jams formed as vehicles streamed out and other residents scrambled frantically to find transport.
A spokesman for the UN refugee agency, the UNHCR, said an estimated one million people had been affected: 200,000 who had fled the battlezone; 300,000 who were on the move or about to go; and some 550,000 displaced by earlier fighting in the tribal belt and across the province.
The numbers are soaring at an alarming rate. By late afternoon 102,000 displaced people had registered for assistance, up from 45,000 a day earlier, said Killian Kleinschmidt, a senior UNHCR official in Islamabad. The agency needs $180m (£119m) for the immediate crisis, he said.
Some 5,000 people are living in camps set up in Mardan and Swabi, south of Swat, and more are planned. Even there, refugees and aid workers may not be safe. Mardan has suffered suicide attacks and local officials warn that Taliban sympathisers are hidden among the influx.
The concerted army operation was triggered by US pressure but also shifting public opinion at home. It was signalled on Thursday by the prime minister, Yousaf Raza Gilani, who vowed to "eliminate militants and terrorists" from their Swat stronghold. "Enough is enough!" read the front page of yesterday's Daily Times, a left-leaning English-language paper.
More importantly, opinion has shifted in the Urdu media. The opposition, including religious parties, have largely assented to the operation. "Previously Pakistanis saw this as the US war, but now there is a general impression that this is our war, and we must stop the Taliban march," said Amir Rana, an expert on jihadi groups.
But the consensus remains fragile and may be temporary, particularly if the fighting produces civilian casualties.
Yesterday the army dropped leaflets across the valley, urging residents to reject the Taliban. "There are people who want to create panic in the country and destroy it. Do you want that?" said one flyer.
An estimated 4,000 militants were operating in Swat, said Abbas, including child soldiers who had been forcibly recruited. The Taliban were funded through the drug trade, kidnapping and money from Afghanistan, he said.
Analysts said the early goal was to "decapitate" the Swat Taliban by killing their leader, Maulana Fazlullah, thought to be in nearby mountains, or a senior lieutenant. "The military wants to eliminate one or two senior people from Fazlullah's group to raise the morale of their troops and show they mean business," said Zaffar Abbas, a senior editor with Dawn newspaper. "But it won't be easy."
The larger question is whether the operation signals a shift in the Pakistani security establishment's policy towards jihadi groups, some of which have been secretly supported by the state as military proxies in India and Afghanistan.
Pakistan is also under pressure to crack down on groups such as Lashkar-e-Taiba, which carried out the Mumbai attacks in November.