Iranian forces have seized a Marshall Islands-registered container ship in the Gulf in an incident that is likely to add to international tensions in the sensitive region.

Saudi Arabian television initially reported the incident, saying the vessel involved was flying the US flag. However, the Pentagon subsequently identified the vessel as the Maersk Tigris, a Marshall Islands-flagged ship operating a service for Denmark’s Maersk Line.

Vessel tracking services showed that the vessel — which was due to call at Dubai’s Jebel Ali but not at any Iranian port — was sitting off the Iranian island of Qeshm, outside the port of Bandar Abbas. The vessel had changed course sharply while navigating the narrow strait, according to the services.

The Pentagon said the Tigris had been approached by several Iranian Revolutionary Guard Corps Navy (IRGCN) patrol vessels while transiting the Strait of Hormuz heading into the Gulf.

“The master was contacted and directed to proceed further into Iranian territorial waters,” the Pentagon said. “He declined and one of the IRGCN craft fired shots across the bridge of the Maersk Tigris.”

The master had complied with the Iranian demand and proceeded into Iranian waters near Larak Island, near Qeshm, it added. A US naval vessel, the USS Farragut, was monitoring the situation but there were no Americans on board.

There are regular incidents in the narrow Strait of Hormuz at the entrance to the Gulf involving vessels straying into or close to Iranian territorial waters. The highest-profile incident in recent years involved mariners from the Royal Navy’s HMS Cornwall who were seized in 2007 by Revolutionary Guards while searching a merchant vessel in what Iran claimed were Iranian territorial waters.

Maersk Line said in a statement that the vessel had been approached in international waters, contradicting the Pentagon statement, which had described the incident as having taken place in Iranian waters.

“According to our information the vessel is currently being escorted towards Bandar Abbas in Iran by Iranian patrol boats,” the company said.

The Tigris was operating a service that runs between the Russian Black Sea port of Novorossiysk and Jawaharlal Nehru port, near Mumbai.

Maersk said its paramount concern was the crew’s wellbeing.

Maersk charters the Tigris from the Singaporean arm of the Hamburg-based Rickmers Group — one of the scores of German companies that own container ships and lease them to operators.

Maersk said it was working “in close dialogue” with Rickmers to obtain information about the seizure and explore options to resolve the situation.

It was also in dialogue with Denmark’s Ministry of Foreign Affairs, it said.

Jerry Hendrix, a retired US Navy captain now at the Center for a New American Security in Washington, said that the seizure of the ship posed “a direct challenge to US leadership”, given the security guarantees the US has made to the Marshall Islands. Iran’s actions had “the net effect of undermining US prestige in the Arabian Gulf region while raising Iran’s. The Obama administration will be well served by quick and decisive action to recover the ship”.

Cliff Kupchan, chairman of Eurasia Group, said the incident was possibly a way of “saving face” for Iran after the presence of a US aircraft carrier off the coast of Yemen last week prevented a possible delivery of weapons by Iranian vessels to the Houthi rebels in Yemen.

“The sides will likely resolve this issue quickly,” he said, although the incident could stoke opposition in Congress to the ongoing nuclear negotiations with Iran.

Container ships are generally less prone than tankers and dry bulk carriers to boarding by other craft because of their high, sheer sides and relatively high speed. The last widely publicised international incident involving a container ship was the seizure by Somali pirates in April 2009 of the Maersk Alabama, a US-flagged Maersk Line vessel, and its crew of US citizens.

Get alerts on Iran when a new story is published

Copyright The Financial Times Limited 2018. All rights reserved.

Follow the topics in this article