Pakistan's army is allowing hundreds of thousands of civilians to flee the Swat valley as it steps up a campaign against the Taliban. Up to 200 Islamic militants have been killed in Swat and the neighbouring Shangla district in the past 24 hours, the military said. About 200,000 people have left Swat in recent days and up to 500,000 are expected to flee. They join 555,000 people displaced earlier from Swat and other areas after fighting broke out in August. Zubair Khan, who lives in the valley's main town Mingora, said: "Everybody wants to get out of this hell. "Some are driving out while many are just on foot. They don't know where they're heading but staying here just means death." The army went on a full-scale offensive on Thursday after the government ordered troops to flush out militants from the Taliban stronghold. The offensive was launched while President Asif Ali Zardari, the widower of former prime minister Benazir Bhutto, was in Washington assuring a nervous United States his government was committed to fighting militancy. Helicopters and warplanes targeted militant hideouts in Mingora and other areas in Swat and Shangla on Sunday, the military said. Two soldiers had died, it said. Military spokesman Nasir Khan said: "It's a tough battle. They're operating in small groups. They don't fight a pitched battle but we're closing in on them, squeezing them and have cut their supply lines." The Taliban had also planted bombs along roads and in Mingora to inflict civilian casualties and then put the blame on security forces, the military said.