Children still face attacks, abduction and rape in Democratic Republic of Congo, often at the hands of government forces, according to a UN report.
Despite some progress, such abuses "continue to a large extent with impunity" said UN Secretary General Kofi Annan.
The report details 29 child abductions and 60 deaths in the last year.
Although a five-year war ended in 2003, some children are still being abducted and forced to fight, it said.
The problems appear to be the result of efforts to combine former militias with government forces, Mr Annan said.
The country's five-year civil war was notorious for its use of child soldiers.
Mr Annan raises particular concerns over the Congolese armed forces, reporting that their chief of staff was notified of more than 26 cases of recruitment of child soldiers and other violations in the last year.
The 17,000 UN peacekeepers in the country regularly conduct operations jointly with the government forces.
The report covers the period from July 2005 to May 2006 and says many of the abuses were concentrated in the lawless east of the country where rebel groups are strongest.
Among the perpetrators it names are Mai-Mai militiamen and Rwandan elements either linked to the chiefly ethnic Hutu Democratic Forces for the Liberation of Rwanda (FDLR) or the Tutsi dissident General Laurent Nkunda.
Although some progress has been made on combating such abuses, the report said there was little trust in the judicial system and many rights violations went unchallenged.
Mr Annan urged all parties to release children still present in armed forces and groups.
According to a national commission on demobilising children, which was established in 2003, more than 18,000 children have been released from armed groups.
"Thousands more have escaped from fighting forces on their own and are discreetly returning to civilian life," Mr Annan said.
An estimated 4 million people died in the war, most from hunger and disease.
The country is preparing for its first multi-party elections in 40 years on 30 July.