The United Nations Children's Fund released a list of 1,387 children last week that it said were rebel soldiers amid increasing violence in Sri Lanka that threatens an already shaky truce with the government.
The rebel Liberation Tigers of Tamil Eelam (LTTE) said it had checked the list and determined that more than 800 of those named were aged over 18.
"Given that more than 800 of the youths in the list are now over the age of 18, UNICEFs call for the release of these youths is not based on any international human rights standards," the LTTE said in a statement.
It also said 54 children on the list had been released from rebel ranks and claimed a random check showed UNICEF had counted some names several times to boost its numbers.
"It can only be viewed as a desperate attempt to boost the numbers in their list with the view to discredit the LTTE," the statement said.
"When viewed against the silence of the UNICEF in the face of horrendous attacks on children by the government of Sri