The UN World Food Programme (WFP) has stopped food distribution in a tribal district in Pakistan where 45 people died in a suicide attack on Saturday. An official told the BBC the suspension was temporary and that distribution would resume at the earliest. A female bomber blew herself up near a large crowd receiving food aid in Khar town in the north-western Bajaur area. US President Barack Obama condemned the attack as "outrageous". "As of now, we are in contact with the authorities both in Peshawar and in Khar and our intention is to reopen the four WFP hubs in Bajaur region as quickly as possible," WFP spokesman in Islamabad, Amjad Jamal, told the BBC. "Such situations have arisen in the past, but we have always resumed our operations within two hours to 36 or 48 hours of the suspension, depending on the level of security threat." Mr Jamal said Saturday's blast took place at a security post about 600m away from the WFP distribution hub. "We had to close the place because it was put under curfew after the blast. "We then suspended operations at the rest of our three hubs in Bajaur as well, as a precautionary measure," he said. Pakistan's Taliban said they ordered the attack on the distribution centre, which is used by the World Food Programme and other aid agencies. They said the rebels had targeted the local people - displaced members of the Salarzai tribe - because of their support for the Pakistani military. An estimated 300 people were queuing for food at the time of the blast, with reports saying at least 100 people were injured in the bombing. The tribal district of Bajaur, where the attack took place, has seen several military operations to clear it of insurgents. The army had previously declared the operations a success and the area safe for the displaced to return.