Government and rebel forces in South Sudan stand accused of recruiting and using child soldiers in combat, despite renewed promises from both sides.

Human Rights Watch says that children as young as 13 are being given weapons and little or no training before being forced into conflict.

In some towns, soldiers are forcibly abducting children from their homes."In Malakal, government forces are even taking children from right outside the United Nations compound," said the organisation's Africa director Daniel Bekele.

The report has been dismissed by government officials, who say they have no need to recruit underage fighters. "How can we recruit child soldiers at a time when we have sufficient manpower?" said Minister for Information Michael Makuei."We have no child soldiers."

In Sudan it is illegal for anyone under the age of 18 to join the army, and the use of children under the age of 15 is considered a war crime under international law.

Despite this, more than 12,000 children, the majority of them boys, have been recruited and used as soldiers by the army and various militia in the last year alone, reports Al Jazeera. Since January, Unicef says it has negotiated the release of 300 child soldiers from one rebel group, but many more are still fighting.

The conflict in South Sudan began in 2013 when President Salva Kiir's forces clashed with rebel soldiers loyal to the ousted vice president Riek Machar. What began as a political power struggle soon divided along ethnic lines, with the Dinka and the Nuer communities effectively at war.

"South Sudanese children's lives are being devastated by conflict, with children once again going to war instead of to school," Bekele said. "Both sides should stop recruiting children, and hold those responsible to account."