Sri Lanka's military says it has captured the Tamil Tigers' biggest sea base. The seizure of the base in Chalai effectively cuts off the main supply route of the Tamil Tigers, who are on the verge of defeat in their 25-year war for a separate homeland. Military spokesman Brig. Udaya Nanayakkara says troops took over the sea base on Thursday "in a major victory for the government." The rebels are cornered in a 85-square-kilometer sliver of coastal land in the Vanni region of northern Sri Lanka. Also trapped with the rebels are some 250,000 civilians. The government has rejected calls for a cease-fire despite mounting casualties among civilians caught in the crossfire. Hundreds are believed to have died in the fighting.