They say the man killed was Benjamin Hrangkhawl, a senior leader of the National Liberation Front of Tripura (NLFT) separatist group.

The NLFT is considered to be one of Tripura's most powerful insurgent bands.

State officials say that following a tip-off, police and para-military troops encircled a rebel base on Saturday in the Herma area straddling Tripura's borders with Bangladesh.

They say that Mr Hrangkhawl had set up the base some time ago.

Police officers say he crossed into the Herma region from neighbouring Bangladesh with more than 20 heavily-armed fighters and was planning to stage attacks against security forces.

Foreign sanctuary

But as Indian soldiers got close to the NLFT base, they were met with heavy fire.

The encounter lasted several hours and carried on into Sunday morning before the rebels fled into nearby forests.

Guerrillas attack security forces

During their search, security forces recovered the body of a rebel not far from the base.

Some arms, ammunition, documents, maps and Indian and Bangladeshi currency were recovered from a bag near the body.

But Tripura police were able to identify the body as that of Benjamin Hrangkhawl only on Monday morning.

The state Police Intelligence Chief Kishore Jha described the killing of Mr Hrangkhawl as a major success.

The Chief Minister of Tripura, Manik Sarkar, has sought to influence Delhi into pressing Bhutan and Bangladesh to arrest and extradite Indian militants allegedly taking refuge in those countries.

The chief ministers of other northeast Indian states are supporting Mr Sarkar in his campaign.

While Bhutan accepts the presence of some Assamese militants in its territory, Bangladesh denies that its territory is being used by any anti-Indian rebels.