COLOMBO: Sri Lankan rebels declared a unilateral cease-fire today as a top UN official pressed Sri Lankan leaders to let aid into the northeastern war zone where tens of thousands of civilians are trapped.

Sri Lanka’s Defence Secretary Gotabhaya Rajapaksa rejected the call, saying the rebels were “running” from government forces, who have pushed deep into the Tamil Tigers’ strongholds in the north in recent months, surrounding the beleaguered rebels and vowing to end the quarter-century war. The United Nations and others have been pushing for a negotiated truce to allow civilians to escape, as reports have grown of starvation and casualties among those trapped by the fighting. A rebel statement e-mailed to The Associated Press today said all their military operations would “cease with immediate effect.” The rebels asked the international community pressure the government into also halting their campaign, saying the “humanitarian crisis can only be overcome by the declaration of an immediate cease-fire.” UN Under-Secretary General for Humanitarian Affairs John Holmes held meetings Sunday with senior officials in Colombo and was “underscoring the urgent need for humanitarian access by the UN to the combat zone,” U.N. spokesman Gordon Weiss said.

Aid workers have been barred from the region since fighting escalated in September. The UN says nearly 6,500 civilians have been killed in the fighting over the past three months. Holmes, who arrived yesterday, had previously called on the government to suspend its offensive to allow the estimated 50,000 trapped civilians to escape. He was to head tomorrow to the northern region of Vavuniya to inspect displacement camps and hospitals that have been overwhelmed by the more than 100,000 civilians who fled the war zone over the past week. The UN says another 50,000 civilians remain trapped in the war zone. But the rebels say the number of trapped civilians is three times that estimate. The rebels, listed as a terrorist group by many Western nations, have been fighting since 1983 for an ethnic Tamil state in the north and east after decades of marginalisation by governments dominated by the Sinhalese majority. After more than three years of intense fighting, the military stands on the verge of crushing the group.