By Subir Bhaumik BBC correspondent in Eastern India

At least 11 separatist rebels have been killed in an encounter with security forces in India's north-eastern state of Manipur.

Police officials say some guerrillas of the outlawed Naga rebel group the National Socialist Council of Nagaland (NSCN), were travelling toward Burma when they were stopped by security personnel.

The police and the NSCN both blame each other for provoking the encounter.

Observers say such incidents might undermine the spirit of the ceasefire that is now in effect between Indian security forces and NSCN rebels in north-eastern India.

Allegations

The group of NSCN rebels was travelling late on Saturday down a road leading to Burma from the state's capital Imphal.

The Naga insurrection began in the 1950s

At a check-post near the town of Palel, soldiers from the paramilitary Manipur Rifles asked the truck to stop.

A state police spokesman says the rebels opened fire, forcing the security men to retaliate.

The spokesman said all 11 NSCN guerrillas in the truck were killed and 16 weapons were recovered from the vehicle.

But an NSCN spokesman alleged that Manipur Rifles personnel had opened heavy fire at the truck without any provocation.

He said that, as a result, the rebels were caught by surprise.

Peace talks

The rebel spokesman said the new Congress government in Manipur was trying to scuttle the dialogue between the NSCN and the Indian government.

Delhi's military response has had limited success

He alleged that the state government in the neighbouring state of Nagaland was acting in a similar fashion.

Peace talks between the Indian government and the NSCN have been taking place for the last four years.

Recently, NSCN leaders have accepted the invitation of the Indian Prime Minister, Atal Behari Vajpayee, to hold talks in India.

So far the talks have been held in foreign capitals like Bangkok, Amsterdam and the Hague.