"The lifting of the detention order against Steno Impero was finalized today, but the investigation of some of its violations and environmental damage remains open," ministry spokesman Seyyed Abbas Mousavi said in a tweet.
"The owner and captain of the ship have made a written commitment to accept the court's decision in this regard," he said.
Iranian forces seized the Stena Impero on July 19 for marine violations two weeks after British marines detained an Iranian tanker off Gibraltar. The Iranian vessel was released in August, according to Reuters.
The owner of the Stena Impero also said on Wednesday the tanker is still being held in Iran, despite Tehran’s lifting of a detention order on the vessel.
Sweden’s Stena Bulk CEO Erik Hanell said it was not in negotiations with Iran and not aware of any formal charges against the crew or the company.
He said the ship was fueled and ready to sail for a port in the United Arab Emirates as soon as it was cleared to leave.
Iran freed seven of the 23 crew members earlier this month and Stena Bulk has tried to get the rest out as well, in part by offering a crew exchange.