Sri Lanka's Tamil Tiger rebels have warned that a truce with the government is under threat after the recent killing of one of its leaders.
Both sides have been called to observe restraint
E Kaushalyan was the most senior Tiger killed since the ceasefire began in February 2002.
Tuesday was the third anniversary of the truce and pressure is on both sides to observe restraint.
More than 60,000 people have died since the rebels began their fight for a homeland for minority Tamils.
In the northern rebel-held town of Kilinochchi, the Tamil Tigers' political wing leader, SP Thamilselvan, accused the government of engaging in a "secret war".
"The present incidents indicate that the ceasefire is at breaking point," Reuters news agency quoted him as saying.
The rebels have blamed the government for carrying out the killing.
The government has denied the accusation and has said it was carried out by a rival rebel faction.
'Killings must stop'
Former Sri Lankan Prime Minister Ranil Wickramasinghe, who signed the ceasefire agreement, said the ceasefire must be protected.
"Parties with vested interests would like to go back to war," he said.
"But the reality is, this country cannot face another war. We will all be destroyed by the fight."
Norwegian monitors of the peace process say the recent violence jeopardises the peace process and say the killings must be stopped.
"Assassinations and killings... have without a doubt poisoned the atmosphere between the parties and led to an unsafe environment creating fear among the general public," Hagrup Haukland, the head of the monitoring mission, said in a statement.