New York  - UN Secretary General Ban Ki-moon called on Sri Lanka's warring parties on Friday to open a safe corridor and allow an estimated 250,000 civilians trapped in the fighting to escape.

Ban welcomed President Mahinda Rajapaksa's announcement of safe passage for all civilians trapped in the area of intense fighting in the North to a secure environment. But he said serious concern remained for the 250,000 civilians caught in the area close to the fighting.

He urges the two sides - the government of Sri Lanka and the Liberation Tigers of Tamil Eelam (LTTE) - to do "all in their power, to make the safe passage a reality, and to ensure the protection of civilians in accordance with international humanitarian law."

Ban asked LTTE to let civilians move out of the conflict zone to areas they feel safest and called on the government to protect civilians arriving from Vanni and other conflict areas.

"Such standards include guaranteeing their freedom of movement, providing basic services, and allowing full access by humanitarian agencies," Ban said in a statement. "For its part, the United Nations stands ready to provide the necessary humanitarian assistance. The secretary general strongly underlines the need for urgent steps toward a speedy and orderly end to the fighting." (dpa)