Addressing the Independence Day parade, President Mahinda Rajapakse said Sri Lanka was facing the challenge of eradicating terrorism and poverty. A large military parade is under way to mark the Independence Day anniversary. At least 11 people were killed in a suicide bomb attack onboard a train at the main railway station on the eve of celebrations. On Saturday, 18 died in a bus blast in Dambulla.
Both attacks were blamed by the government on the Tamil Tigers rebels, though the rebels have denied involvement.
Security forces are on high alert after a series of bombings. Much of the centre of Colombo has been sealed off by military checkpoint.
Thousands of police and troops are on the streets and the navy has stepped up coastal patrols to combat a possible sea-borne attack.
This year Independence Day celebrations are the first major national event since Colombo formally ended the Norwegian-arranged 2002 truce and vowed to crush the Liberation Tigers of Tamil Eelam (LTTE) militarily.
The military will deploy 4100 troops for a ceremonial parade, in addition to drawing thousands of commandos and paramilitary police forces from the provinces to beef up security.
Sri Lanka has remained in ethnic turmoil for more than half the period since independence, with more than 60,000 people killed since 1983.