By Sushil Sharma BBC News, Kathmandu

The rebels have been fighting for a republic since 1995

It has urged the rebel leadership to investigate such abuses and take action against the guilty.

In an open letter Amnesty International said it had been receiving reports of abuses by the Maoists.

It alleged the rebels - who have consistently denied abuses - have been engaged in killings and abductions.

In an open letter to Maoist leader Prachanda, the director of Amnesty International's Asia Pacific region, Ingrid Massage, urged him to guarantee the safety of all civilians and unconditionally release those who had been abducted.

She said that many of those targeted had criticised Maoist policies.

This, she added, was a clear violation of international humanitarian law.

Ms Massage also condemned the abduction of civilians - particularly school children.

Rising concern

The rebels are known to abduct school students in large numbers and make them attend indoctrination classes before releasing them after a few days.

Many are forcibly recruited to the rebel ranks.

Amnesty International's concerns follow reports of Nepal's worsening human rights situation due to the Maoist insurgency in which 10,000 people have died in the past nine years.

Both the rebels and the security forces have been criticised for rights abuses and in the past Amnesty International has been critical of the government troops.