COLOMBO, NOV 15: Security has been further tightened in the Sri Lankan Capital ahead of Tuesday's filing of nomination papers by presidential candidates contesting next month's elections, officials said.Police announced on Monday that roads near the Elections Office in Colombo will be closed for motorists except the candidates and a limited number of supporters. President Chandrika Kumaratunga is seeking re-election at the December 21 election which she called 10 months ahead of schedule. She is challenged by Opposition leader Ranil Wickremesinghe and at least five other candidates.Police said they will also not allow parking along the routes to the elections office to prevent car bomb attacks on the candidates. Each candidate is allowed to bring in only 15 supporters. The police action followed a bomb attack Sunday against an Opposition United National Party (UNP) meeting in the North-central town of Eppawela. UNP leader Ranil Wickremesinghe said he narrowly escaped assassination but a bystander waskilled and 43 others were injured.President Kumaratunga ordered an immediate police investigation into the first serious election-related incident of violence since snap polls were announced last month.