The mass exodus of civilians fleeing fighting in Pakistan’s Swat valley is causing a humanitarian crisis, according to UN aid agencies.As government aircraft target Taliban positions, terrified villagers say they are caught in the crossfire. Thousands of people have been trying to take advantage of a break in a curfew to get out of the region. One man described how shells rained down and tanks were blown up in front of his eyes: “The army or the Taliban – we don’t know which side it’s coming from – it’s not safe here,” he said. Since the collapse of February’s peace pact aimed at ending Taliban violence in Swat, the military has launched assaults in the outskirts of the region’s main town of Mingora. Up to 40,000 people have been displaced from Swat and nearby areas since the trouble flared. The majority are now being housed in temporary camps set up with the help of the United Nations and aid agencies. But they are warning they will not be able to cope with the estimated 800,000 people who might try to make it out of the valley.