Guterres' Children in Armed Conflict report covering 2017 identified Jaish-e-Mohammed and Hizbul Mujahideen as the groups using children in their armed campaign in Kashmir.

It said: "The United Nations continued to receive reports of the recruitment and use of children, including by the Naxalites, particularly in Chhattisgarh and Jharkhand. Naxalites reportedly resorted to the use of a lottery system to conscript children in Jharkhand."

It added: "In addition, three incidents of the recruitment and use of children were reported in Jammu and Kashmir in the context of clashes with national security forces. One case was attributed to Jaish-e-Mohammed and two to Hizbul Mujahideen."

However, the report presented by Guterres this week to the General Assembly also mentioned "unverified reports" that indicate national security forces use children as "informants and spies".

Guterres said he would "encourage the government to put in place measures to hold perpetrators of child recruitment and use to account and engage with the United Nations in view of ending and preventing violations against children".

Overall in India, the report said, "Children continued to be affected by incidents of violence between armed groups and the government, particularly in Chhattisgarh and Jharkhand and during tensions in Jammu and Kashmir."

"Children continued to be killed and injured in the context of operations of national security forces against armed groups," the report said.

It said that according to government data, 188 civilians were killed in Naxalite-affected regions but a break up of how many of them were children was not available.

In Kashmir, the report cited one case, that of a 15-year-old boy "killed by national security forces" during a clash with alleged Lashkar-e-Taiba elements in Padgampora village in Pulwama district.

Children were also affected in other ways by conflicts like the closure of schools because of actions both by Naxalites and by securiy forces, Guterres's report said.

"In Jharkhand, suspected Naxalites elements attacked one school in Khunti district, partially destroying it," the report said.

"The occupation of over 20 schools was documented by the Central Reserve Police Force in Srinagar, Kashmir, in April," the report said.

Because of increased tensions in Kashmir, 65 schools in Rajouri district and 76 in Poonch were closed for varying periods, it added.

Guterres said he welcomed India signing the Worst Forms of Child Labour Convention in June 2017.

The convention adopted by the International Labour Organisation in 1999, prohibits bonded labour of children and their trafficking, sexual exploitation and recruitment for armed conflict.