Taleban fighters have been using deadly white phosphorus munitions, some of them manufactured in Britain, to attack Western forces in Afghanistan, according to previously classified United States documents released yesterday.

Last night the US military in Kabul condemned the use of white phosphorus by the insurgents as “reprehensible”. White phosphorus is banned as an offensive weapon under international rules of armed conflict.

Major Willis confirmed that the US and Nato’s International Security Assistance Force used white phosphorus in Afghanistan but never as an anti-personnel weapon. “That’s not allowed under the terms of international law,” she said.