London, Feb 9 : The NATO-led force in Afghanistan has claimed that a UN report accusing the US troops of killing hundreds of children in drone strikes over the past four years is false.

The UN Committee on the Rights of Children, in its latest report, said that the number of child casualties had doubled in 2010-2011 due to a "lack of precautionary measures and use of indiscriminate force".

The NATO force called the claims `categorically unfounded' and `false', the BBc reports.

The issue of civilian deaths by Nato forces has caused tensions between the US and Afghan President Hamid Karzai.

The International Security Assistance Force (Isaf) said allegations of indiscriminate force used by US troops during their Afghan operations were "unsubstantiated."

It said in a statement that ISAF and US Forces Afghanistan take precautions to employ force only when necessary, and in a proportional manner.

While coalition forces are "sometimes responsible for civilian deaths", insurgents kill the majority of civilians, Isaf added. (ANI)