An oil tanker that disappeared in the Arabian Gulf was towed to Iranian waters for repairs, Tehran has claimed.
It emerged on Tuesday that US officials feared the Panamanian-flagged, UAE-based Riah had been seized by Iran after it vanished in unexplained circumstances in the Strait of Hormuz.
The tanker had simply encountered technical difficulties and had been taken to be fixed, an Iranian defence official said, according to semi-official Iranian news agency ISNA.
The statement did little to clarify exactly what happened to the Riah, or why its tracking device had been deactivated. Further details will be announced later, Iranian Foreign Ministry spokesman Abbas Mousavi said.
The ship’s tracking device was turned off on Saturday night.
Both the United States and the UAE, where the tanker is based, say that the vessel has not been in contact with its owner since its transponder turned off.
The disappearance came amid rising tensions between Tehran and its rivals over Iran's unravelling nuclear deal with world powers, and follows a series of suspicious incidents involving tankers in the Gulf over recent months.
The latest incident was first reported by CNN, which said US intelligence increasingly believed the tanker had been forced into Iranian waters by Iran’s Islamic Revolutionary Guard Corps but that other Gulf sources suggested the ship had broken down and was towed by Iran.
Earlier, an official from the UAE said the ship, last seen drifting towards Iranian waters, is not owned or operated by the UAE and had not sent out a distress call.
“Could it have broken down or been towed for assistance? That’s a possibility. But the longer there is a period of no contact it’s going to be a concern,” the US official, quoted by AP, said.
Samir Madani, co-founder of shipping monitoring website TankerTracker.com, said the vessel had disappeared and usually simply went from coast to coast within the UAE. It then deviated from its usual course, going into Iranian waters for the first time in the last year.
"What led it there, we don't know. What happened at that point, we don't know either," he told The National.
Tracking the vessel by satellite has proven difficult because of its small size. It is roughly nine metres wide with a capacity of 2,000 tonnes, Mr Madani said, compared with 200,000 tonnes for a supertanker.
The ship, he said, was significantly smaller than the large international ocean-going tankers that can be between up to 60 metres wide.
Tankers are usually tracked using on-board locating devices that broadcast routes, speed and other crucial information. The systems are designed to increase safety at sea and prevent collisions. These are sometimes turned off when passing through dangerous areas or to otherwise obscure a ship’s location, origin or loads.
Capt Ranjith Raja of the data firm Refinitiv said that the Riah had not switched off its transponder in three months of trips between Dubai, Sharjah and Fujairah. This was a "red flag", he was quoted as saying.
Recent tensions have seen the US send thousands of additional troops, nuclear-capable B-52 bombers and advanced fighter jets into the Middle East. Mysterious attacks on oil tankers and Iran shooting down a US military surveillance drone has added to the fears of an armed conflict breaking out.
In a separate development on Tuesday, Iran’s Supreme Leader Ayatollah Ali Khamenei said his country would retaliate over the seizure of an Iranian supertanker carrying 2.1 million barrels of light crude oil. The vessel was seized with the help of British Royal Marines earlier this month off Gibraltar over suspicion it was heading to Syria in violation of European Union sanctions, an operation Mr Khamenei called “piracy” in a televised speech.
“God willing, the Islamic Republic and its committed forces will not leave this evil without a response,” he said. He did not elaborate.
Meanwhile, the US plans to brief foreign diplomats based in Washington this week on a new maritime security initiative to protect shipping in the Middle East, following a spate of attacks on tankers in recent months.
In May and June, six tankers were attacked just outside the Gulf. About one-third of the world’s seaborne crude and fuels passed through the Strait of Hormuz last year, highlighting its key role in global oil markets. While Iran has been blamed by some for attacks on merchant shipping, it has denied responsibility.
US Central Command has been working on a plan to deter threats to shipping in the Arabian Gulf, the Strait of Hormuz and the Gulf of Oman, according to Brian Hook, the US special representative for Iran.
"When I was in the Gulf, I heard very clearly the need for enhanced maritime security," Mr Hook said at an Axios event on Tuesday. "The secretary has heard it, when he and the president were at the G-20, there were conversations about it," he said, referring to Secretary of State Mike Pompeo and President Donald Trump.