Colombo - Navy and ground troops battled Tamil rebels in separate confrontations Tuesday as security forces were closing upon the main rebel stronghold in northern Sri Lanka, military officials said.

New clashes between advancing security forces and rebels were reported in three locations in Mullaitivu district, 375 kilometres north-east of the capital Colombo.

The military said "fierce fighting" was reported in the areas and at least seven dead rebels were recovered. One rebel base with fortified bunkers also was found during the operation. The military made no mention about casualties of soldiers.

The fighting was reported hours after the navy destroyed four rebel boats, including a boat used for suicide attacs, off the north-eastern coast of Mullaitivu. Two bodies were recovered from the sea.

Navy spokesman Captain DKP Dassanayake said that the navy was maintaining a sea blockade preventing rebels escaping or smuggling military hardware to the region.

Government troops have made steady progress in the last few weeks after capturing some of the key rebel held towns and are now heading to the rebel stronghold of Mullaitivu. (dpa)