The issue of child soldiers has come under renewed focus since Wednesday, when the Sri Lankan government went on a publicity blitz by inviting newspapers to photograph two underage combatants who fled from rebel camps and took shelter with the Sri Lankan navy earlier in the week.
Their accounts of being kidnapped and held by the rebels contradicted pledges made by the guerrillas to UN agencies that they had stopped recruiting children.
UNICEF said the Tamil Tigers are known to have recruited 5368 child soldiers since 2002, when the rebels and the government signed a cease-fire agreement brokered by Norway.
Yasmin Haque, a UNICEF official, said the rebels have made several releases of child soldiers, and there also have been many cases of children escaping. But UNICEF's database shows that 1358 child combatants are still with the rebels, he said.
Haque said the government's media blitz was regretful, with photographs of the two teenagers - aged 15 and 17 - printed on the front pages of several newspapers.
The two boys escaped from two different camps in northeastern Trincomalee and eastern Batticaloa, military spokesman Brigadier Sudhir Samarasinghe said.
They were flown to Colombo on Wednesday and made to pose for the media. Asked by military officials, the two teenagers displayed their weapons skills, including handling automatic rifles.
A top rebel leader, Seevaratnam Puleedevan, expressed surprise at the case and said they were reviewing the issue of child soldiers again.