The British tanker Stena Impero and its crew remain detained in Iran, Al-Arabiya TV has reported, citing the British Foreign Ministry.
"We continue to call on Iran to immediately release the detained tanker," the ministry said, as quoted by the TV channel.
Earlier in the day, the Iranian government's spokesman, Ali Rabiei, said that Iran had completed the legal procedures necessary for releasing the UK-flagged tanker.
The Swedish Foreign Ministry, for its part, said it had not yet received confirmation that the Stena Impero oil tanker, which is owned by Stena Bulk, a Swedish shipping company, had been released from Iran's custody, a spokesperson for the ministry said.
"There is no confirmation at the moment," the spokesperson said.
In early September, seven crew members of the detained Stena Impero oil tanker, including a Russian sailor, left Iran.
The Stena Impero was seized by the Iranian Islamic Revolutionary Guard Corps in the Strait of Hormuz on 19 July over an alleged violation of international maritime rules.
The move came two weeks after Iran's own Grace 1 oil tanker had been seized by UK marines over an assumed breach of the European Union's sanctions against Syria.
Iran's tanker was released on 19 August after Gibraltar reportedly received assurances the cargo would not be delivered to Syria.