By Simon Gardner

COLOMBO, Dec 14 (Reuters) Sri Lanka's security forces are determined to drive the Tamil Tigers from a stretch of the east coast the rebels control under a 2002 truce, the military said today, to the worry of international ceasefire monitors.

Troops and rebels have been locked in fierce artillery duels in the northeastern districts of Trincomalee and Batticaloa in recent weeks, and around 35,000 civilians are stuck in camps behind rebel lines in and around the Tiger-held town of Vakarai.

The United Nations has urged both sides to halt fighting that has killed more than 3,000 civilians, troops and rebel fighters this year, but the military and Liberation Tigers of Tamil Eelam have ignored the call.

''We want to get the LTTE out of this area and free the civilians,'' military spokesman Brigadier Prasad Samarasinghe told Reuters, referring to a 22 km stretch of coast in the eastern districts of Trincomalee and Batticaloa.

''The LTTE are firing artillery and mortars towards civilian settlements and camps in Trincomalee south and keeping 35,000 people as human shields,'' he added. ''So we have to respond to that threat as a countermeasure. We will control most of the coastline in the east.'' Analysts suspect the government wants to drive the Tigers out of the east completely and then concentrate on rebuilding damaged, long-neglected infrastructure in the area while confining the Tigers to their northern stronghold.

Samarasinghe said more than 1,000 civilians had fled Tiger territory near Vakarai overnight and said troops had killed five rebels and freed a soldier as the Tigers had tried to move him south to areas of land they control inland.

The Tigers say dozens of civilians have been killed by army artillery fire in and around Vakarai since Saturday, while the army blames the rebels for putting them in harm's way.

The Tigers were not immediately available for comment on the plan of the military, which has already driven them back from terrain they had held south of the strategic harbour of Trincomalee since the 1990s.

''It's definitely not in the spirit of the ceasefire agreement, that's for sure, apart from jeopardising the lives of thousands of people in the area,'' said Thorfinnur Omarsson, spokesman for the Nordic Sri Lanka Monitoring Mission (SLMM) which oversees the now tattered truce.

''Civilians are caught in the middle of this and we want both sides to stop shelling,'' he added.

More than 67,000 people have died since the conflict began in 1983 after the LTTE launched its struggle for a separate homeland for minority Tamils.

REUTERS BDP HT1627