The US military has accused militants in Afghanistan of using white phosphorus munitions in attacks on American forces and in civilian areas, saying it has documented at least 44 "reprehensible" incidents of insurgents using or storing the weapons.
White phosphorus is a spontaneously flammable material that leaves severe chemical burns on flesh. Using white phosphorus to illuminate a target or create a smokescreen is considered legitimate under international law, but rights groups say its use in populated areas can indiscriminately burn civilians and constitutes a war crime.
The US military, in documents supplied to the Associated Press, said there had been at least seven instances of militants using white phosphorus in improvised explosive attacks since spring 2007, including attacks in civilian areas.
The military documents showed 12 attacks where militants used white phosphorus in mortar or rocket attacks.
The most recent documented attack came last Thursday when a Nato outpost in Logar was hit with two rounds of indirect white phosphorus fire. Most troops in Logar, which lies south of Kabul, are American.
Afghan authorities said Taliban fighters may have used a burning agent, possibly white phosphorus‚ in a US-Taliban battle last Monday in Farah province, after doctors discovered unusual burns among the dead and wounded.
Nader Nadery, an official with the Afghanistan Independent Human Rights Commission, said doctors were treating 16 patients with severe burns. The commission is investigating the possible use of white phosphorus or another incendiary chemical against villagers during the battle, which, according to the Afghan president, Hamid Karzai, killed up to 130 civilians.
Nadery said Farah's governor told the group's researchers that many of those killed had severe burns. The governor said Taliban fighters attacked the villagers with a flammable material, although it was not necessarily white phosphorus.
A US spokeswoman, Major Jenny Willis, said the use of white phosphorus as a weapon could cause "unnecessary suffering".
She said: "This pattern of irresponsible and indiscriminate use of white phosphorus by insurgents is reprehensible and should be noted by the international human rights community."
Willis said the US military and Nato had been able to document 44 cases of white phosphorus use by insurgents, including 38 uses in eastern Afghanistan, where most American troops are stationed.
The US military used white phosphorus in the battle of Falluja in Iraq in November 2004. Israel's military used it in January against Hamas targets in Gaza.