COLOMBO (AFP) - Sri Lankan government troops on Thursday captured the last known Tamil Tiger naval base in the northeast of the island, a military official said. In a fresh blow to the embattled ethnic rebels, troops fought their way to the Chalai base of the Sea Tigers, the naval unit of the Liberation Tigers of Tamil Eelam (LTTE). The military said at least four senior Sea Tigers and eight other rebels were killed. "The army has just moved into the Chalai base," the official said. "Troops are now consolidating their hold in the coastal area." The LTTE had a formidable sea-going capability and had scored many successes by sinking naval fast attack craft and even foreign merchant vessels operating in waters close to the coastline they once controlled. With the fall of Chalai, the Tigers are left with just 20 kms of coastline in the northeastern district of Muallaittivu. The defence ministry said that the Tigers tried to use suicide bombers to prevent the army from taking Chalai, but the attacks had been thwarted. "As LTTE's heyday is nearing its Waterloo, (the) desperate Tiger leadership appears to be using its last trumpets by sending brainwashed teenagers for suicide missions," the ministry said.