Colombo, April 17: A top UN official met with Sri Lankan leaders today to discuss efforts to free tens of thousands of civilians trapped by the raging civil war amid reports that children in the conflict zone were dying of severe malnutrition. The government has cornered the Tamil Tiger rebels in a tiny sliver of land along the northeastern coast and vowed to crush the group after more than a quarter-century of fighting on the Indian Ocean island nation. But concerns have grown about the escalating toll the war is taking on the estimated 100,000 ethnic Tamil civilians crowded into what remains of rebel-controlled territory. The United Nations estimates at least 4,500 civilians have been killed in fighting over the past three months and 12,000 have been wounded. The figures were provided today by an international official based in Colombo on condition of anonymity because they have been circulated to local diplomats but not publicly released. UN Secretary-General Ban Ki-moon sent his chief of staff Vijay Nambiar to Sri Lanka to discuss the fate of the civilians and efforts to free them from the war zone. Nambiar met Friday with President Mahinda Rajapaksa, but no details of the meeting were released. The government announced a two-day cease-fire earlier this week to allow the civilians to flee, but only a few hundred crossed the front lines before the truce expired on Wednesday morning. In an implied criticism of the government’s decision to resume its offensive, neighbouring India called today for a new cease-fire to let civilians escape the “evolving human tragedy.” “Continuation of precipitate military actions leading to further civilian casualties at this time would be totally unacceptable,” Indian External Affairs Minister Pranab Mukherjee said in Calcutta, India. He also called on the rebels to release the trapped civilians. International rights groups have accused the rebels of using the civilians as human shields, and accused the government of disregarding the civilians’ safety in its drive to destroy the Tamil Tigers. Both sides deny the accusations.