The Sri Lankan government said Monday it will immediately stop using air strikes and heavy weapons against the Tamil rebels to prevent further casualties among the thousands of civilians trapped in the war zone.

The announcement came hours after the government rejected a ceasefire appeal from the rebels.

Diplomatic pressure has grown in recent days for a humanitarian truce to allow the trapped ethnic Tamil civilians to escape the fighting.

UN humanitarian chief John Holmes, in Sri Lanka on a three-day visit, urged government officials on Sunday to reopen the war zone to humanitarian groups. Aid workers have been barred from the region since fighting escalated last year.

Conflicting accounts

With the rebels cornered in a small strip of land along the northeast coast, the government said in a statement Monday "that combat operations have reached their conclusion," and it instructed the military "to end the use of heavy-calibre guns, combat aircraft and aerial weapons which could cause civilian casualties."

However, the rebel-linked TamilNet Web site reported that as recently as Monday morning, the military fired artillery shells and air force jets dropped 14 bombs into the war zone, killing several civilians and wounding more than 200 others.

It isn't possible to verify this account, as independent journalists are not allowed into the war zone.

Government forces stand poised to crush the rebels and end this Indian Ocean island nation's quarter century civil war. A recent government offensive forced the rebels out of much of their strongholds in the north and cornered them along the coast.