Police in India's north-eastern state of Tripura say at least 14 people have been killed in a separatist attack.

They say that more than 20 rebels of the outlawed National Liberation Front of Tripura (NLFT) opened fire indiscriminately after surrounding the market in Singhicherra.

Six died on the spot, and 20 others were injured, with eight of those dying later of their wounds.

The rebels, based over the border in Bangladesh, are fighting for a separate homeland for tribal people.

All those killed in the attack were Bengali speakers.

Hundreds of police have launched a search for the attackers.

Additional police and paramilitary contingents have been rushed to the spot, as ethnic tension was said to be high after the attack.

The NLFT, the strongest of the many tribal rebel groups in the state, have periodically attacked Bengali settlers.

The rebels want to evict them from the state to restore the demographic majority of the state's indigenous tribals.

Hundreds have died in the rebel attacks in the past decade since the NLFT first surfaced in 1992.