UN Secretary General Ban Ki-moon voiced concern Friday that the Liberation Tigers of Tamil Eelam (LTTE) were keeping civilians in a conflict zone against their will and called for their freedom.
"While some have been able to leave or escape, reliable reports indicate that the LTTE have prevented others from leaving, including firing at them," Ban said in a statement, adding that civilians have suffered heavy casualties.
"The severe restrictions of the LTTE on their freedom of movement violate international law," he said.
Ban also deplored that the LTTE forced recruitment of civilians, including children, in its fight against the government. He also urged the government to meet its responsibility of protecting civilians, dpa reported.
The UN said thousands of civilians remain trapped in the Vanni region and are facing heavy risk and casualties.
Earlier Friday, military officials in Sri Lanka said at least 37 rebels were killed as government troops sought to capture the last remaining rebel-held territory there. Police commandos shot dead 13 more rebels in the south-east, military officials said.
The LTTE has been fighting for more than 25 years for a separate state for the Tamil ethnic minority in the northern and eastern parts of majority-Sinhalese Sri Lanka.