By Frances Harrison BBC correspondent in Colombo

The United Nations children's agency says it has received fresh assurances from Tamil Tiger separatists in Sri Lanka that they will not recruit children under the age of 18.

Human rights groups have repeatedly accused the Tigers of recruiting boys and girls as young as 12.

This woman lost her child in the conflict

Unicef says it has managed to get more than 60 demobilised throughout the last year.

This is by no means the first time the Tamil Tigers have promised not to recruit child soldiers.

Four years ago, the rebels promised the UN special representative for children and armed conflict they would not recruit anyone under the age of 17.

But at the end of last year, for example, human rights groups like Amnesty International, said the Tigers had recruited several hundred children in just a few months, sometimes using coercion.

World watching

What is different about this renewed commitment by the Tigers is that for the first time in years, outsiders now have access to rebel territory because of the peace process.

If the Tigers fail to live up to their assurance this time, the world will not only be watching, but aid workers, diplomats and journalists will be visiting them to ask what went wrong.

And for the first time, Amnesty officials are currently visiting rebel areas to discuss the issue of child recruitment, among others.

In this atmosphere, Unicef says it wants to keep the issue alive.

It plans to run a centralised database of cases of alleged child recruitment based on complaints by parents and local aid organisations.

It says it will continue to try and secure the release of underage soldiers.