Italian opposition lawmakers and human rights groups are voicing outrage after Italy released a Libyan warlord wanted by the International Criminal Court.

A senior member of Libya's judicial police has been given a hero's welcome back home after Italy unexpectedly released him from jail just two days after arresting him on a warrant from the International Criminal Court (ICC).

The International Criminal Court (ICC) 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.