The nations leading Sri Lanka's peace process on Friday urged the Tamil Tigers to free 100,000 civilians they are holding and the military to stop shelling the no-fire zone where the separatists are making their last stand, Reuters reported. The statement from the United States, Britain, Japan and Norway came as Sri Lanka's military said it had begun what it called "the largest hostage rescue operation in the world" by identifying the best routes for people to get out. The four-nation group, dubbed the Tokyo Co-Chairs, discussed on a conference call "how to best end the futile fighting without further bloodshed", a U.S. State Department statement said. "They call on the Tamil Tigers to permit freedom of movement for the civilians in the area," it said. "They reaffirmed the need to stop shelling into the 'no fire zone' to prevent further civilian casualties." Tens of thousands of civilians are trapped inside a 17 square km (7 sq mile) army-declared no-fire zone on the northeastern coast, held there by the Liberation Tigers of Tamil Eelam (LTTE) and being killed in shelling, the co-chairs' statement said.