At least 14 people, including a senior Sri Lankan government minister, have been killed in a suicide bombing near the capital Colombo, officials say.
Highways Minister Jeyaraj Fernandopulle was attending a function to mark the forthcoming Sinhala and Tamil New Year in the western district of Grampaha.
The defence ministry blamed Tamil Tiger rebels, who want an independent state for Sri Lanka's Tamil minority.
Mr Fernandopulle is the second minister to have been assassinated this year.
The former minister for nation building, DM Dassanayake, was killed in a bombing on 8 January, days after the government pulled out of a crumbling ceasefire with the Tamil Tigers.
The government has since vowed to crush the separatist rebels by the end of this year or the next. At least 70,000 people have died since the war began in 1983.
The explosion happened as Mr Fernandopulle was attending a New Year celebration at the Kanthi playground in the town of Weliveriya, 30km (18 miles) outside Colombo.
Jeyaraj Fernandopulle was a vocal critic of the Tamil Tigers
He was about to wave a flag to start a marathon race when the bomb went off.
"It was a suicide bombing of the [Tamil] Tigers," Media Minister Anura Yapa told the AFP news agency.
The director-general of the government's Media Centre for National Security, Lakshman Hulugalle, told the BBC that the minister was killed by the explosion along with many of those around him, including at least one runner.
At least 90 other people were seriously injured by the blast and have been rushed to a local hospital, among them Gampaha police Senior Superintendent Hector Darmasiri, the defence ministry said.
Mr Fernandopulle, who had been in charge of roads and highways in the country and was a senior figure in the government, was a vocal critic of the Tamil Tigers.
The 55-year-old Roman Catholic lawyer first became a member of parliament for the Sri Lanka Freedom Party in 1983 and served in several ministerial roles since 1997.