The United Nations Children's Fund has opened a controversial rehabilitation centre for child soldiers in Sri Lanka.
Unicef says children have been most at risk during the conflict
The Tamil Tiger rebel group has sent 50 children to be demobilised in the centre in Kilinochchi, in the north.
Unicef's Ted Chaiban said: "This is a big day for the children who have been among the people at most risk during the conflict."
But the centre has drawn criticism because the rebels' charity wing is involved in the project.
Mr Chaiban, head of the Unicef mission based in Sri Lanka's capital,
Colombo, warned that there were still cases of child recruitment by the Liberation Tigers of Tamil Eelam (LTTE).
"If the rehabilitation of the child soldiers is to succeed then your recruitment of children has to stop," he told the rebels.
More centres planned
The rebels deny recruiting underage soldiers in recent years and say the 50 children are part of a group of 700 who repeatedly tried to enlist with their organisation.
They say every time they send these children home they return again, eager to join up to escape poverty and social problems at home.
Unicef's hope is that the transit centre, 330 kilometres (200 miles) north of Colombo, will be a place to assess released child soldiers and arrange for their return to civilian life.
Ultimately there will be three centres across the north-east, each holding up to a 150 children for a maximum period of three months.
The rehabilitation programme is part of a wider peace process in Sri Lanka but it has become controversial because the rebels' charity wing will jointly run the transit centres.
The BBC's Frances Harrison in Colombo says critics in the south of the country say it is wrong to involve the very organisation that violated the rights of the children in caring for them now.
The worst-case scenario, she says, would be the Tigers recruiting new child soldiers to fill Unicef's transit centres rather than release the children in whom they have invested time and money for military training.
A local newspaper, the Sunday Leader, has accused Unicef of "underwriting and funding the abduction of innocent children".
The Tigers have returned at least 350 child soldiers to their parents since November 2001, but Unicef still has a list of over 1,150 children who have reportedly been conscripted.
Some fear innocent children may be recruited to fill the UN centres
The opening of the UN centre came as the United States said it was continuing to designate the Tamil Tigers a terrorist organisation.
The US embassy in Colombo said: "Although the LTTE are engaged
in a peace process with the government of Sri Lanka... the United States has determined that it continues to engage in terrorist activities."
The US first designated the Tigers a terrorist group in 1997.
The Tigers said they were disappointed.
"We view this US move with great regret," said Sutha Thangan,
the deputy leader of the LTTE's political wing.
"We would like the United States to have a realisation of the
positive steps in the continuing peace process."