The Sri Lankan military says it has captured a Tamil Tiger sea base in the northeastern district of Mannar.
Military officials say Sunday that the army has consolidated its hold on the area of Silavathurai, which it seized Saturday.
The army said it had intercepted radio communications that indicated 11 Tamil rebels were killed in clashes with government forces Friday.
However, the rebels said they lost only one fighter, and killed a government soldier.
The Tamil Tigers also said nine civilians who were fleeing the area were killed in a military mine attack. The military blames rebels for the incident.
A military spokesman, Brigadier Prasad Samarasinghe, said the new operation is a "humanitarian offensive" to liberate about six thousand people being held in the area.
Fighting between the Sri Lankan government and Tamil Tiger rebels has intensified recently despite a 2002 cease-fire.
Tamil Tigers have been fighting since 1983 for a separate homeland for Sri Lanka's minority Tamils. About 70,000 people have been killed in the conflict.
Some information for this report was provided by AFP and AP.