The UN estimates there are at least 50,000 civilians trapped along a sandy strip of land near the northeastern town of Mullaitivu where government forces have encircled the remaining Liberation Tigers of Tamil Eelam (LTTE) troops, who have been fighting for an independent Tamil homeland for more than two decades.
The government calculates the number of civilians trapped at between 15,000 and 20,000.
"These are people who are in mortal danger as long as fighting goes on," Holmes told the media at the end of his two-day visit. "We want to get these people out as soon as possible."
Holmes held discussions with President Mahinda Rajapaksa, Foreign Minister Rohita Bogollagama, Minister of Disaster Management and Human Rights Mahinda Samarasinghe, and also toured camps in the northern town of Vavuniya where most of those who fled are staying.
From 27 October 2008 to 27 April 2009, 151,231 Tamil civilians had crossed into government-controlled areas from the conflict zone, the UN Office for the Coordination of Humanitarian Affairs (OCHA), reported.
Suspension of heavy weapons use
Holmes welcomed a decision by the government to suspend the use of heavy weapons and aerial bombardment from 27 April.
"What we need to see is that [decision] actually implemented on the ground so that the civilian casualty rate drops," he said.
The UN has consistently asked the government to exercise maximum restraint to avoid a bloodbath, particularly by not using heavy weaponry.
"The danger of heavy weapons is absolutely clear," Holmes said, adding that their use was almost certain to cause civilian casualties in the government-designated "no-fire zone".
"We believe the civilian casualties to be very high, certainly in the thousands in the last three months. Those figures are unacceptably high," Holmes said, but declined to give an exact number.
UN assessment mission
Holmes, however, failed to reach an agreement with the government to allow a UN assessment team to visit the combat zone.
The government has agreed in principle to such a visit but told Holmes it was not safe to cross the frontline.
UN officials in Colombo said that during the time the team was within the combat zone, there should be a cessation of fighting. Holmes said the chances for a truce of any kind were remote.
"We would like to see a humanitarian pause," he said.
During his visit Holmes informed the government that an additional US$10 million would be released from the UN Central Emergency Relief Fund (CERF) in addition to the $10 million released earlier to assist civilians who had fled the fighting since 20 April.
"This is an enormous challenge; 100,000 people turning up in a couple days," he said. "What you see now is that the situation is stabilising."
Holmes toured the camps and said more tents had been set up and food, water and sanitation facilities were also being provided.
On 27 April, the UN Refugee Agency (UNHCR) began an emergency airlift operation targeting more than 150,000 internally displaced persons (IDPs) in camps in Vavuniya, Jaffna, Mannar and Trincomalee.
There are reports of overcrowding at some IDP sites, OCHA reported. Camps in Vavuniya are reportedly holding an average of 18 people per tent (designed for a family of five) with limited water supplies, according to the UN humanitarian team.
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