Colombo, Mar. 23: Briefing documents prepared by the United Nations have warned of a major humanitarian crisis in Sri Lanka, where over 150,000 people are being shelled at daily and are running short of water and medicine.

The Sri Lankan Government has declared the area in question as a "No Fire Zone", and the UN claims that tens of thousands of people are caught between the last 1,500 fighters of the Liberation Tigers of Tamil Eelam (LTTE) and the advancing troops of the Sri Lankan army.

It says the civilians are trapped on a thin strip of land - estimated at 13.5 square miles (35 square kilometers) - on Sri Lanka''s north-east coast.

The UN warns that if people stay they risk being killed by government shells and if they try to leave they will be in danger of being shot by the Tigers.

Diplomats say there is a real danger that a bloody denouement to the 25-year-old civil war could result in an "all-out humanitarian catastrophe".

Senior UN officials in Sri Lanka have shied away from publicly criticising the government in its hour of victory. In private, many argue that outspoken criticism may backfire and see foreign aid agencies expelled at the time of greatest civilian need.

Sri Lanka has ignored calls for a ceasefire, saying that the Tigers want mass civilian deaths to spark pressure for a truce.

There is little doubt that these are desperate times for the LTTE, which has been fighting for a separate homeland in the north and east of Sri Lanka for the past quarter of a century. The LTTE has been declared a terrorist organisation by the United States, the European Union and India. (ANI)