YANGON: Myanmar ethnic minority rebels have freed eight underage military recruits captured and held as prisoners of war, the International Labour Organization said on Thursday.

The ILO said it had acted as an intermediary between the government and the rebels in the recent release of the soldiers in the northern state of Kachin.

"This led to the release of eight underage recruits by the Kachin Independence Army (KIA) who were held by the KIA as prisoners of war," said the ILO's Yangon liaison officer, Steve Marshall.

He said the organisation was seeking their formal discharge from the military. It was unclear how long they had been held as prisoners of war.

There are believed to be thousands of under-18s in Myanmar's state army and ethnic armed groups following decades of military rule marked by a number of insurgencies in remote border areas.

Fighting has intensified between the military and the KIA since a 17-year ceasefire broke down in June 2011.

In June last year, Myanmar's new reformist government signed an agreement with the UN pledging to prevent the use of child soldiers and allow access to military units to check for underage recruits.

Forty-two child soldiers have since been discharged from the government forces, according to the ILO and state media.

But the London-based advocacy group Child Soldiers International said in a report Wednesday that minors were still being recruited, and that the army, border troops and rebel groups all still used children.

"Even if the process may be slowing down, and not so many are being recruited, there are still children slipping through the recruitment procedure," Marshall said.

He said the KIA was also suspected of recruiting child soldiers on occasion but had cooperated in returning minors to their families.