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.

White phosphorus, which can burn its victims down to the bone, has been found in improvised explosive devices (IEDs) in regions across Afghanistan including in the south, where British troops are based. It has also been used in mortar and rocket attacks on American forces.

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 Jennifer Willis, a spokeswoman for the US Army at Bagram, near Kabul, said that markings on some of the white phosphorus munitions that had been recovered showed that they had been manufactured in a number of different countries, including Britain, China, Russia and Iran.

Although a full investigation is under way, it is not yet clear how the Taleban and other insurgent forces using them had acquired the white phosphorus munitions from Britain. However, Major Willis said that Afghanistan was littered with ordnance of every kind and it was not a surprise that the insurgents had got their hands on white phosphorus.

The US military said that the Taleban had found white phosphorus rounds left over from the war with the Soviet Union in the 1980s. But there were newer models which, it is suspected, had been smuggled across the border from Pakistan.

Major Willis said that the use of white phosphorus in IEDs was a relatively new development. The earliest report of the insurgents using white phosphorus was in February 2003, but the eight known IED cases, including one in the south, have all occurred since March 2007.

The Ministry of Defence in London said that there was no evidence that British soldiers had been burnt by white phosphorus munitions in Helmand, but said that there would have to be an investigation into how British-manufactured munitions were in the hands of the Taleban.

Royal Ordnance factories owned by BAE Systems make 81mm mortars that the British fire with white phosphorus rounds for illumination in Afghanistan. But the MoD denied that the Taleban had somehow acquired British mortars sent to troops in Helmand. The US evidence showed that the only white phosphorus shells found in that province were 120mm and 105mm munitions. “These are not used by British forces,” the MoD said.

The US military released details of 44 known cases — six in southern Afghanistan — which included incidents where Nato troops and Afghan civilians had received severe burns. US sources said that there was strong evidence that the Taleban had been responsible for the deaths of more than 100 civilians in the battle that took place in Farah province last week and that they had used white phosphorus.

The Americans were initially blamed for killing the civilians in airstrikes. But local doctors discovered unusual burns among the dead and injured, which pointed to the use of white phosphorus.

Colonel Greg Julian, the senior US military spokesman in Afghanistan, said that the Americans had not used the material in the battle on May 4.

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.

White phosphorus, she said, was only used for marking targets, screening troops from enemy positions, illuminating areas, destroying unoccupied bunkers and buildings and “for igniting enemy ammunition or petroleum production”.

The use of white phosphorus in war became a highly controversial issue during the attacks on Gaza by the Israeli Defence Forces in January.

Israel denied firing white phosphorus shells into civilian areas but when The Times revealed the increasing number of civilian casualties suffering from strange burns, it admitted using the material and announced an investigation into why the munitions had been fired into densely populated areas.

Six in south

March 16 An IED rigged to a 107mm white phosphorus (WP) round defused in Zabol province

March 11 Cache, including ten rounds of 120mm WP mortar ammunition, in Helmand, where US troops based

December 2, 2008 Insurgents fire a WP rocket at an Isaf base in Kandahar

June 1, 2008 Isaf team destroys munitions, including 105mm WP projectiles in Helmand, where British troops are stationed

November 18, 2007 Afghan child finds a WP rocket in Kandahar

June 15, 2004 Large cache, including 46 rounds of 82mm WP ammunition, discovered in a home in Zabol

Times Recommends

• Would you live on the wrong side of the Berlin Wall?
• Wish you were here, says Iraq tourist board
• Russian policeman’s corruption plea to Putin