World Vision is calling for the urgent protection of children who are at risk of being forced to fight for rebel groups in Mali.
The Christian development agency says child protection must be at the heart of training given by EU troops to Malian forces.
The EU this week announced a training mission in Mali to improve the military capacity of the Malian Armed Forces.
The United Nations reports that child soldiers have been recruited by all rebel groups.
Other human rights violations noted by the UN include summary executions, rapes, and acts of torture.
Chance Briggs, director of World Vision Mali, said children were particularly vulnerable to recruitment into militia groups as well as various forms of sexual violence, including forced marriage.
"They are therefore in urgent need of protection," said Briggs.
World Vision UK wants to see the UK Government take the lead in ensuring child protection is built in alongside combat training.
Justin Byworth, Chief Executive of World Vision UK, said: "This is especially important when child combatants are captured. They must be dealt with according to International humanitarian law.
"It's important to work with Malian troops and the Malian legal system to ensure that all grave violations of the rights of civilians, especially those of children, are identified, prevented and stopped."
The UN reports that children as young as 10 have been seen manning checkpoints and children have also been seen conducting joint patrols in the name of "Islamic police".
Some parents are reportedly giving their children to the rebels for religious reasons, while others have been promised money. Rebel groups are said to have also actively recruited children in religious schools, where there are concerns that children are trapped without adult protection because many teachers have fled.
World Vision welcomed the appointment of an EU Special Representative for Mali and called for dialogue with NGOs and civil society groups working on the ground in the country.
World Vision's EU Representative Marius Wanders said: "We sincerely hope the EU Special Representative will listen to our concerns and incorporate them. We know grave violations have taken place already. Mechanisms must now be put in place to prevent them."