The United Nations Children's Fund, Unicef, has renewed appeals to Tamil Tiger rebels in Sri Lanka to stop recruiting child soldiers.
The Tigers say they return any "underage volunteers" to parents
Unicef said the Tigers had taken more than 5,000 children into their ranks since agreeing a 2002 truce.
It said the rate of recruitment had fallen recently but added that the practice should not occur at all.
Peace talks are due in Geneva next week and Unicef called on all sides to prioritise the issue of child soldiers.
"While recruitment of children has been reduced and the average age of recruitment has increased from 14 to 16 over the past four years, recruitment of even one child is unacceptable according to the Convention of the Rights of the Child," the Unicef statement said.
Unicef says it has recorded 5,368 cases of reported child recruitment in Sri Lanka since January 2002.
The statement said Unicef officials had shared their concerns with the rebels on Sunday.
The rebels have yet to respond. In the past, they have strongly denied recruiting children and promised to return "volunteers" to their parents if they were found to be underage.