Islamabad, Aug 18 - Flash foods triggered by heavy rain last week have claimed over two dozen lives and destroyed more than 400 houses in northwestern Pakistan, the UN said Tuesday.

'The floods have caused reported deaths of 27 people, with up to nine people reported missing. Up to 450 homes were also destroyed, along with a massive loss of crops and livestock,' Online news agency quoted UN deputy spokesperson Marie Okabe as saying.

The Office for the Coordination of Humanitarian Affairs (OCHA) quoted local officials as saying that some 80,000 people have been affected by floods in Swabi district, with officials declaring a state of emergency in a number of towns there.

The UN is assessing the damage and experts are warning of a possibility of food shortage. Current humanitarian needs include medicine, tents, drinking water and aqua tablets, Okabe said.

The floods have submerged cultivated land, with maize, rice, sugarcane and tobacco crops being destroyed. Livestock has also been washed away, OCHA said.