Interior Minister Matteo Piantedosi defended before parliament the release on Tuesday of Osama Najim, who is wanted by the International Criminal Court (ICC) for war crimes and crimes against humanity charges related to his management of migrant detention camps.

Najim was arrested in the northern city of Turin on Sunday but returned to Tripoli Tuesday on an Italian air force plane after the court of appeals in Rome ruled that he could not be held.

The court found the detention of Najim was "irregular" and "not provided for by law", ordering him freed, Piantedosi told the Senate.

Najim was "then repatriated to Tripoli for urgent security reasons", he said, citing "the dangerousness of the subject".

Najim is believed to have been in charge of Tripoli's Mitiga detention centre, and is wanted on charges including murder, rape and sexual violence and torture, committed since 2015.

Italian opposition parties have demanded that Prime Minister Giorgia Meloni explain before parliament the reasons for the release of an accused war criminal wanted by the international court.