Fears abound for tens of thousands of civilians held inside a 25 square kilometre patch of coastal scrubland in Sri Lanka, all that remains of the Tamil Tigers’ dreams for a separate state

If the last act in Sri Lanka’s 25-year war is playing out, the only question left is whether it ends in siege or slaughter, a report published in Indian media said.

There is little doubt Sri Lanka’s military will shortly destroy the Liberation Tigers of Tamil Eelam (LTTE) as a conventional fighting force.

But fears abound for the civilians held in a military no-fire zone.

Since January, diplomats in Colombo have been working furiously to persuade the LTTE to let civilians out, and to get the government to throttle back its assault.

Among the worst-case scenarios are that thousands could be killed in a final assault, or slaughtered by the rebels themselves in a bid to blame the government. The most bleak outlook sees the LTTE, which perfected suicide as a weapon, enacting an apocalyptic mass suicide.

"It is a like a bank heist where everything has gone wrong," a Western diplomat said on condition of anonymity. "The people and the crooks are inside, and the police are outside, but the wrong thing would be for the police to go rushing in with guns."

External interference appears remote. China and Russia last week opposed having Sri Lanka discussed at the UN Security Council and neighbouring India’s only intervention has been to send aid and a medical team to help the displaced.