Seven of the 23 crew members of the British-flagged tanker Stena Impero that was seized by Iran in July reached Dubai on Thursday after Tehran agreed to their release, a Russian official said. The Swedish-owned Stena Impero was detained by Irans Revolutionary Guards on July 19 in the Strait of Hormuz for alleged marine violations, two weeks after Britain detained an Iranian tanker off the territory of Gibraltar. That vessel was released in August. An official with Russias embassy in Tehran told Reuters that the seven crew members -- one Russian, one Latvian and five Indian nationals -- obtained their visas in Tehran on Wednesday and then flew to Dubai. The remaining 16 crew members will remain onboard the ship "until the fate of the tanker itself is decided", the Russian official said. The Stena Imperos 23 crew are of Indian, Russian, Latvian and Filipino nationality, the vessels Swedish owner Stena Bulk has said. Stena Bulk separately confirmed on Thursday that the seven crew members had been released and were traveling to a safe location. "We continue to work tirelessly to obtain the release of the remaining crew onboard the Stena Impero and will continue to provide all possible support to their families during this difficult time," Erik Hanell, Stena Bulks chief executive and president, said in a statement. "As we have stated previously; from the information we have, there is no current evidence the Stena Impero breached any maritime rules or regulations." The US Treasury Department on Thursday warned that anyone around the world who helps fuel Iranian vessels blacklisted by Washington runs the risk of being designated as well. US Defense Secretary Mark Esper said he currently had no plan on his desk to seize Adrian Darya 1. “We do not talk about plans, but currently I have no plan right now sitting on my desk to do such a thing,” Esper told reporters in London.