A leading campaign group has demanded an urgent inquiry into a report that US troops indiscriminately used a controversial incendiary weapon during the battle for Fallujah. Photographic evidence gathered from the aftermath of the battle suggests that women and children were killed by horrific burns caused by the white phosphorus shells dropped by US forces.

The 1980 UN Convention on Certain Conventional Weapons bans the use of weapons such as napalm and white phosphorus against civilian - but not military - targets. The US did not sign the treaty and has continued to use white phosphorus and an updated version of napalm...

The Pentagon has always admitted it used phosphorus during last year's assault on the city, which US commanders said was an insurgent stronghold. But they claimed they used the brightly burning shells "very sparingly" and only to illuminate combat areas.

But the documentary Fallujah: the Hidden Massacre, broadcast yesterday by the Italian state broadcaster, RAI, suggested the shells were commonly used and killed an unspecified number of civilians. Photographs obtained by RAI from the Studies Centre of Human Rights in Fallujah, show the bodies of dozens of Fallujah residents whose skin has been dissolved or caramelised by the effects of the phosphorus shells. The use of incendiary weapons against civilian targets is banned by treaty.

Last night Robert Musil, director of the group Physicians for Social Responsibility, called for an investigation. He told The Independent: "When there is clear testimony that use of such weapons has done this, it demands a full investigation. From Vietnam onwards there has been a general condemnation of [the use of white phosphorus] and concern about the injuries and consequences."

The 1980 UN Convention on Certain Conventional Weapons bans the use of weapons such as napalm and white phosphorus against civilian - but not military - targets. The US did not sign the treaty and has continued to use white phosphorus and an updated version of napalm, called Mark 77 firebombs, which use kerosene rather than petrol. A senior US commander previously has confirmed that 510lb napalm bombs had been used in Iraq and said that "the generals love napalm. It has a big psychological effect."

John Pike, director of the Washington-based military studies group GlobalSecurity.Org, said the smoke caused by the bombs could confuse or blind the enemy or mark a target. "If it hits your clothes it will burn your clothes and if it hits your skin it will just keep on burning," he said.

Experts said that, if not removed, white phosphorus - known as Willy Pete - can burn to the bone. The fumes from phosphorus cause severe eye irritation.