Story highlights UN chief: Libya auction a reminder of need to manage migration humanely

Libya says it is working to pursue human traffickers, rescue migrants

(CNN) The UN secretary-general said Monday he is "horrified" at reports showing African migrants sold as slaves and called for immediate investigations.

The reports demonstrate some of "the most egregious abuses of human rights" and may amount to crimes against humanity, Secretary-General António Guterres said.

"I abhor these appalling acts and call upon all competent authorities to investigate these activities without delay and to bring the perpetrators to justice," Guterres said. "I have asked the relevant United Nations actors to actively pursue this matter."

Urging the international community to unite on the issue, the UN chief called on all countries to adopt the UN Convention against Transnational Organized Crime and its protocol on human trafficking.

He further said the Libya story provides a reminder of the need to manage migration flows in a humane manner that addresses the root causes, increases opportunities for legal migration and cracks down on smugglers.