An oil tanker once at the center of a crisis between Iran and the US was boarded in the Gulf of Oman by “unauthorized” people in military uniforms early on Thursday morning, an advisory group run by the British military said. Details remained unclear in what was apparently the latest seizure of a vessel in the tense Middle East waterways.

However, suspicion immediately fell on Iran as the ship was once known as the Suez Rajan and had been involved in a yearlong dispute that ultimately saw the US Justice Department seize 1 million barrels of Iranian crude oil on it. Satellite data showed the ship heading to Iran.