Sri Lanka's minority Tamil community marked 15 years since the end of the island nation's civil war on Saturday in an emotional ceremony that proceeded despite fears authorities would attempt to prevent its staging.

Public events celebrating the Tamil Tigers separatist group -- which fought a no-holds-barred battle to establish an ethnic minority homeland -- are illegal and authorities have blocked past memorials.

Tamils say the events are held to remember all victims of the decades-long war, which concluded in 2009 after a military offensive in the last Tigers stronghold. The operation was condemned internationally for the indiscriminate bombardment of civilians.

"Thousands died here the day before the war ended," a 41-year-old Tamil village official, who asked not to be identified for fear of reprisal, told AFP at the memorial site in Mullivaikkal.

"There were lots of wounded people crying for help," he added. "This will haunt me for the rest of my life."

Several thousand Tamils had travelled to the village for the remembrance, where they lit oil lamps to commemorate the dead.

- 'Impunity is prevailing' -

Sri Lankan authorities have repeatedly disrupted similar memorials in the island's former war zones over the years and arrested participants, but Saturday's ceremony went ahead without incident.

This year it was attended by Amnesty International's global chief Agnes Callamard, the most senior foreign dignitary so far to attend a remembrance event in Sri Lanka's battle-scarred north.

The rights watchdog has for years pressed Sri Lankan authorities, who have repeatedly refused to permit an international probe into wartime atrocities, to properly investigate and prosecute those responsible for abuses.

"We are here to remind the international community that there are people in Sri Lanka waiting for justice," Callamard told reporters after the event.

Prime Minister Justin Trudeau of Canada, which in 2022 voted to recognise May 18 as Tamil Genocide Remembrance Day, said on Saturday his country would "always advocate for justice and accountability for the crimes committed during the conflict".

"Today, we honour the victims, survivors, and their loved ones, who live with the lasting pain caused by this senseless violence," Trudeau said in a statement.

- Intimidation continues -

Tamil residents near the ceremony site told AFP that security forces had been noticeably more active in their communities as the anniversary neared.

"There is heavy surveillance of the people, and it is intimidation," one Tamil resident said Thursday, asking not to be named for fear of harassment.

Saturday marked 15 years since the killing of the Tamil Tigers' charismatic but reclusive leader Velupillai Prabhakaran, who had led the separatist group in open rebellion against Sri Lankan forces since 1972.

His death in the village of Mullivaikkal was the culmination of the lightning military offensive that killed at least 40,000 civilians in the final months of the fighting, according to UN estimates.

Sri Lankan forces were accused of indiscriminately shelling civilians after telling them to move to "no fire zones" to clear the path of their assault.