By Subir Bhaumik BBC correspondent in Calcutta

Five Indian border guards have been killed when separatist rebels opened fire on their patrol on a main road between the north-eastern state of Manipur and Burma.

Police said a foot patrol of the 37th battalion of the Border Security Force (BSF) was attacked near Lokchao village on the road that connects the state capital, Imphal, with Burma.

Four border guards died on the spot and a fifth succumbed to his wounds in hospital.

The rebels carried away three assault rifles and two grenades.

A caller identifying himself as a spokesman for the outlawed Kanglei Kanna Yaol Lup (KYKL) rebel group, which says it is fighting for Manipur's independence, claimed responsibility for the attack.

"It appears the KYKL ambushed the soldiers and killed them to make their presence felt," C Peter Manipur's additional director general of police said.

Attacks stepped up

Rebels in Manipur have intensified their attacks on security forces, particularly the BSF, ever since border guards launched a major offensive to capture the HQ of Manipur's leading separatist group, the Manipur People's Liberation Front (MPLF), in January.

The rebels said they beat back the border guards from their headquarters at Sajit Tampak on the India-Burma border.

Ever since then, the BSF particularly has been targeted by the rebels.

Analysts say rebels in Manipur have also stepped up their attacks because they are upset with Delhi's ongoing negotiations with the National Socialist Council of Nagaland (NSCN), a Naga rebel group which demands the incorporation of those parts of Manipur inhabited by ethnic Nagas within a greater Naga state.