Human rights groups voiced outrage Wednesday after Italy released a Libyan warlord on a technicality, after he was arrested on a warrant from the International Criminal Court accusing him of war crimes and crimes against humanity.

The government attributed the release to procedural reasons. But critics say it is because Italy depends on Libya to stem the flow of migrants from Africa.

Italy's interior minister said on Thursday a Libyan man detained under an international war crimes arrest warrant and then unexpectedly released had been swiftly repatriated because of his "social dangerousness".

Italian authorities released the director of a notorious detention camp who had been arrested in Turin on an ICC war crimes warrant.

The International Criminal Court demanded answers from Italy on Wednesday over why it freed a Libyan man suspected of crimes against humanity and war crimes, including murder, torture, rape and sexual violence.