DUBAI - Boarders have left a tanker that maritime sources had said was seized off the coast of the United Arab Emirates and the vessel is safe, Britain's maritime trade agency reported on Wednesday.

Three maritime security forces had told Reuters on Tuesday that the Asphalt Princess tanker had been seized by suspected Iranian-backed forces, which Iran denied.  

The AIS tracking status of the Asphalt Princess was "Underway Using Engine" early on Wednesday, according to Refinitiv ship tracking data.

The United Kingdom Maritime Trade Operations (UKMTO) said what it described as a potential hijack incident is "complete" but gave no further details in a warning notice based on a third-party source. It did not name the vessel involved.

The incident took place in an area in the Arabian Sea leading to the Strait of Hormuz, the conduit for about a fifth of the world's sea-borne oil exports.

Iran's senior armed forces spokesman, Abolfazl Shekarchi, had on Tuesday denounced reports of maritime incidents and hijacking in the Gulf area as "a kind of psychological warfare and setting the stage for new bouts of adventurism".

The U.S. State Department had said it was looking into reports of a maritime incident in the Gulf of Oman, but that it was too early to offer a judgement.

Tensions have simmered in the region after an attack last week on an Israeli-managed tanker off the Omani coast killed two crew members and was blamed on Iran by the United States, Israel and Britain. Iran has denied responsibility.

(Reporting by Lisa Barrington, Ghaida Ghantous and Alexander Cornwell; Editing by Christopher Cushing and Raju Gopalakrishnan) ((Alexander.Cornwell@thomsonreuters.com;))