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 said that the Asphalt Princess tanker had been seized by suspected Iranian-backed forces, which Iran denied.

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.