At least 10 people have been killed in a suicide bomb attack in southern Sri Lanka, police say. At least one minister was among more than 20 people injured in the blast at the town of Akuressa, 160km (100 miles) south of the capital, Colombo.
Government officials were attending a function at a mosque to celebrate an Islamic holiday at the time.
The defence ministry said the blast was carried out by Tamil Tiger rebels but no-one has yet admitted responsibility.
"An LTTE [Liberation Tigers of Tamil Eelam] suicide bomber has attacked a mosque at Godapitiya, in Akuressa, in the Matara district," the defence ministry said on its website.
Sri Lanka's oil minister HM Fowzie, who was at the site, told Reuters news agency the bomber appeared to have targeted six ministers as they walked in a procession toward the mosque.
The ministers were attending a ceremony to mark the birthday of the Prophet Muhammad when a bomber on a bicycle set off the explosion behind them, officials told the BBC.
Post and Telecommunications Minister Mahinda Wijesekara was injured in the attack and is said to be in intensive care.
A helicopter is airlifting the critically wounded back to Colombo.
One witness, Ahamed Nafri, told Associated Press he was walking toward the mosque at the time of the blast.
"I heard a huge sound and then I saw people had fallen everywhere. They were covered with blood and flesh and the wounded people were screaming."
The blast comes as Sri Lanka's military continues its operation to defeat the Tamil Tigers in the north-east.
On Tuesday the military said it had restricted the rebels to an area of less than 50 sq km (19 square miles) but that heavy fighting was continuing.
Also on Tuesday, the government announced it had appointed the former deputy leader of the Tamil Tigers - known by his nom de guerre, Col Karuna - as a minister.
Vinyagamoorthi Muralitharan is the new non-cabinet minister for national integration and reconciliation.
The Tamil Tigers have been fighting for a separate homeland for the ethnic Tamil minority in the north and east of the country for a quarter of a century.
Government officials say they are confident the entire north-east can be brought under control soon.
But the rebels have vowed to carry on their fight, and correspondents say the latest blast shows they have maintained their ability to launch attacks far from their traditional strongholds.
On 20 February, two planes belonging to the Tamil Tigers attacked Colombo, killing two people and injuring about 45.
About 70,000 people have died in the conflict in the past 25 years.