At least 24 people were briefly arrested by the Sri Lankan security forces for defying a ban on celebrations to mark the 69th birthday anniversary of the slain Liberation Tigers of Tamil Eelam supremo V Prabhakaran, which is commemorated by his followers as 'great heroes day'.
Prabhakaran used to make his annual policy speech on his birthday on November 26 during the days when LTTE ran a parallel state in parts of the northern and eastern provinces of Sri Lanka.
Maaveerar naal or great heroes' day is observed on November 27 by sections of Sri Lankan Tamils regarded as being generally supportive of the Tigers.
It is the day on which fallen members of the LTTE are commemorated.
At least 24 people were arrested by the security forces for defying the ban on celebrations, officials said.
However, those arrested were later released after a warning, they added.
The residents of Vavuniya, Jaffna, Mannar, Mullaitivu and Kilinochchi were seen lighting lamps at the graves of those who died in the conflict.
At Jaffna University on Sunday, students celebrated the 69th birth anniversary of Prabakaran by cutting a cake.
Similarly, a group of Tamil provincial politicians cut a cake opposite the house of Prabhakaran's birth at Valvettithurai.
Oil lamps were lit at different places in the north and east despite authorities banning holding the celebrations.
The police were accused on Monday of storming a Heroes Day celebration held in the eastern district of Batticaloa.
Tamil groups said that armed with riot gear the police tore down red and yellow flags and pulled oil lamps out of the ground to disrupt the celebrations.
The police obtained court orders at some places banning the celebrations.
The LTTE had run a military campaign for a separate Tamil homeland in the northern and eastern provinces of the island nation for nearly 30 years before its collapse in 2009 after the Sri Lankan Army killed its supreme leader Prabhakaran.