The Sri Lankan military has accused Tamil rebels of breaching the country's cease-fire by firing on a navy ship that was carrying a European truce monitor.
Sri Lankan military spokesman Daya Ratnayake says the ship was on a routine patrol close to Trincomalee in the east of the country when it came under small arms fire.
He claims the Liberation Tigers of Tamil Eelam, the LTTE, were responsible for the attack.
"The LTTE fired 75 to 100 rounds on the boat from the beach, and also the Sri Lankan monitoring mission's representative on board, while he was trying to take cover inside the boat, he received minor injuries as well," he said.
The military spokesman called the attack a "clear violation of the cease-fire agreement" between the rebels and the government.
A spokesman for the European truce monitors called it a "serious incident," but said the monitors could not confirm that Tamil rebels were responsible until investigations are conducted.
It was the latest incident in a series of violent attacks that have put pressure on the fragile truce in the country, where a two-decade-long civil war for a separate Tamil homeland killed more than 60,000 people before the guns were silenced in 2002.
The cease-fire has held for more than three years - but in recent months, European truce monitors have frequently warned that the failure of the government and the rebels to restart peace talks is putting the truce under strain.
The rebels pulled out of the talks in 2003, accusing the government of failing to honor pledges it had made. Numerous attempts by Norwegian and Japanese mediators since then to bridge the differences between the two sides have failed.
Both sides say they remain committed to a peace dialogue, but have been unable to agree on a basis for fresh negotiations.