International election observers have condemned the murder of a Tamil candidate in Friday's general election.
By Frances Harrison
BBC Colombo correspondent
The head of the European Union observer mission said violence and democracy could not co-exist.
Rajan Sathiyamoorthy and his driver were killed in the eastern town of Batticaloa. A third man was injured.
The attack is part of a trend of violence in eastern Sri Lanka that seems to be the result of the recent split in the Tamil Tiger rebel group.
The head of the EU observer mission, John Cushnahan, said it seemed forces outside the election process were intent on subverting the outcome.
Speaking in Batticaloa, Mr Cushnahan said his message to those forces was violence and democracy could not be allowed to co-exist.
The suspicion for this latest election-related murder in the east of Sri Lanka - the third in the last month - falls squarely on the Tamil Tiger rebels.
Mr Sathiyamoorthy was a candidate for the Tamil National Alliance, the party which supports the political aims of the Tamil Tiger rebels.
But he was loyal to the breakaway rebel commander in the east, Colonel Karuna.
The mainstream leadership of the Tamil Tigers had recently described Mr Sathiyamoorthy as a traitor.
And with polling day looming, rival factions of the rebels are now keen to see only their supporters are elected.
The head of the rebels' peace secretariat, S Pulithevan, denied the Tigers had any involvement in the killing, saying they were committed to ensuring the safety of all candidates.
But only the mainstream faction of the rebels could benefit from this killing and it comes as part of a trend of attacks on civilians associated with the breakaway rebel leader.
Last week the mainstream Tigers warned they wanted to remove Colonel Karuna from their soil - a comment widely interpreted as a threat to kill him.