NEW : Fears voiced by U.N. for children trapped in the escalating fighting . The U.S. State Department on Thursday called for a cease-fire between the Sri Lankan government and Tamil Tigers to allow civilians to escape the fighting . Upsurge in hostilities follows cessation for Hindu New Year . UNICEF humanitarian chief : Large number of people crowded in very small area . Tamil Tigers , Putumattalan government locked in conflict lasting Sunday .
NEW : Fears voiced by U.N. for children trapped in the escalating fighting . Upsurge in hostilities follows cessation for Hindu New Year . UNICEF humanitarian chief : Large number of people crowded in very small area . Tamil Tigers , Putumattalan government locked in conflict lasting Sunday .