KABUL – The U.S. military said on Monday it had documented 44 incidents of Afghan insurgents using or possessing white phosphorus ammunition, in response to a Reuters report last week of the first known casualty from the chemical.

U.S. and NATO forces acknowledge they use the chemical -- which erupts into flame on contact with the air -- to create smokescreens, illuminate the battlefield or destroy empty buildings -- but they deny knowingly using it on people.

Because it has legal uses on the battlefield, it is not banned by treaties that restrict the use of chemicals as weapons. But it can cause horrific burns if it comes in contact with flesh.

Its use to deliberately target people is illegal, and its use in populated areas is a persistent source of controversy.

The insurgents possess and use white phosphorus as a weapon against people. It's a law of war that we adhere to but the insurgents blatantly violate, U.S. military spokesman Colonel Greg Julian said.

The list of 44 incidents published by the military included only 11 cases in which insurgents actually fired white phosphorus rounds, and none in which anyone was reported to have been injured or killed.

Reuters reported last week that U.S. military doctors had confirmed that they had treated an 8-year-old girl with white phosphorus burns in hospital. Her case was not on the list the military released on Monday.

In the girl's case, the military says it believes no rounds fired by Western forces fell near her house when she was hurt, and that a mortar fired by militants may have been to blame.

The girl's father told Reuters their house was hit by a volley of artillery fired by Western troops.

Human Rights Watch has urged the military to release more details of the incident.

Monday's list of insurgent use included 38 incidents in the east of the country and six in the south.

Western forces reported insurgents had actually fired the rounds in just 11 cases. In eight, they were used or found in homemade bombs.

In the 25 other cases, they were found unused, usually scattered among caches of other weapons and ammunition.

Since Reuters published its account last week, Afghanistan's human rights commission has said it is investigating whether white phosphorus played a role in an incident last week in which Afghan officials say scores of civilians were killed.

That incident, in western Farah province, has caused a crisis between Afghanistan and the United States. President Hamid Karzai has demanded a halt to all U.S. air strikes, something Washington says it cannot do.

Many of the victims in the Farah incident had severe burns. The U.S. military acknowledges bombing two villages after participating in ground fighting nearby, but says it did not fire any white phosphorus ammunition in the battle.

I can't say whether the insurgents used it, but we certainly didn't, Julian said on Sunday.