Sri Lanka has been placed on maximum alert amid fears that Tamil Tiger rebels may carry out trade mark suicide bombings to mark a key anniversary from Tuesday, officials said. The already tight security arrangements in the capital were further strengthened with the establishment of a special police unit to carry out surprise checks, police said. The new measure was taken ahead of the heroes' week of the Separatist Liberation Tigers of Tamil Eelam (LTTE) from Tuesday. The commemoration of rebels who died in the ethnic conflict also coincides with the birthday of the LTTE supremo Velupillai Prabhakaran. The rebel leader who will turn 46 next Sunday is expected to round off heroes' week celebrations with a speech that is expected to underline the policies of is movement which is fighting for a separate state called 'Eelam'. Police said that they feared the rebels may carry out a high profile suicide bombing or target a remote military installation in the island's northeast during the celebrations. "We are taking several precautionary measures," a police spokesman in Colombo said. The special police unit is one of them to carry out search operations in vulnerable areas of the city. The police announced last month they had information that some 46 Tamil Tiger suicide bombers had infiltrated the capital. Bureau Report