At least two people, one of them a three-year-old boy, have been killed by a car bomb in the Sri Lankan capital, Colombo, police and witnesses say.
The blast came as people were leaving work
The bomb went off near a girls' school in a residential area of the city.
A Tamil government minister opposed to the Tamil Tigers told the BBC the target was one of his party colleagues.
The blast comes as the Tigers and military continue heavy fighting in the Trincomalee district in the north-east of the island.
Douglas Devananda, the leader of the Eelam People's Democratic Party (EPDP) which opposes the Tamil Tigers' armed separatist campaign told the BBC that the target was his colleague S Sivathasan.
Police say the bomb was attached to the van that Mr Sivathasan was travelling in.
Mr Devananda told the BBC's Sinhala service that Mr Sivathasan was in intensive care in a Colombo hospital but that his life was not in danger.
The grandfather of the boy killed in the blast said: "The child is three-years-old. His mother is working as a maid here. We were going home after work when it exploded," Reuters reports.
A number of other people were injured in the blast.
Last month, Mr Devananda's press aide was shot dead by gunmen in Colombo.
Meanwhile a French relief agency, Action Against Hunger, says two more of its workers have been found dead in the town of Muttur in Trincomalee district.
Action against Hunger has suspended operations
On Sunday, 15 aid workers were found dead in their compound lying face down and shot at close range.
There has been widespread international outrage at the killings, which came as government and rebel forces fought over a water dispute.
Both sides have accused each other of the killing of the aid workers.
The two new bodies were found in a car - they had apparently been killed while trying to flee the scene of the attack on the aid group's compound.
Action Against Hunger has suspended all its work in the area and says it is waiting for the results of a post mortem.
The Sri Lankan government has promised an independent investigation into the killings of the workers - 13 men and four women.
Journalists have not been able to get into Muttur. Reports from those residents who have not fled the town speak of rotting bodies in the streets.
Some also say that the Tigers have blindfolded some civilians and taken them away for questioning.
On Tuesday the military said suspected Tamil Tiger rebels had ambushed a government patrol near an air force base in the north-east, killing one person and injuring two others.
More than 800 people are estimated to have been killed in Sri Lanka in low-level fighting in recent months.
Despite the upsurge in fighting both sides still say they are acting defensively and therefore complying with the conditions of a 2002 ceasefire.