American actor and playwright Jeremy O. Harris was released from custody in Japan on Monday after his arrest last month on suspicion of attempting to smuggle drugs into the country, a police spokesperson said.

Harris was detained on November 16 at Okinawa's Naha airport when a customs officer found 0.78 grams of crystal containing the synthetic narcotic MDMA in his bag.

Local prosecutors declined to confirm whether Harris had been charged with a crime.

Japan has some of the toughest drug laws among developed countries, imposing severe penalties for possession and smuggling offences.