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.

Italian media reports and a Libyan official say police in Turin have arrested a Libyan warlord wanted by the International Criminal Court for alleged war crimes.

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.

Ossama Anjiem, who runs a major Libyan prison, was in Italy to watch a soccer match. He returned home after an Italian court found issues with the warrant for his arrest.

A Libyan warlord was arrested in Italy on an ICC warrant but was expelled back to Libya after a tribunal's refusal to approve the arrest.

The head of Libya's judicial police has been arrested after the International Criminal Court (ICC) issued a warrant over war crimes allegations, media reports say. Osama Najim, who directs Tripoli's Mitiga detention centre, was reportedly arrested on Sunday in the Italian city of Turin.

Al-Masri had been arrested Sunday in Turin, where he reportedly had attended the Juventus-Milan soccer match the night before. The ICC warrant, dated the day before, accused al-Masri of war crimes and crimes against humanity committed in the Mitiga prison in Libya starting in 2015 that are punishable with life in prison.