US and UK naval forces went to the aid of a Greek bulker being “harassed” by Iranian ships on Sunday.

The US Navy said on Monday that the incident happened in the Strait of Hormuz.

It blamed Iran’s Revolutionary Guard for sending three fast-attack vessels with armed troops to approach the merchant vessel at a close distance.

It issued black-and-white images from a US Navy Boeing P-8 Poseidon overhead, showing the encounter.

The navy’s guided-missile destroyer USS McFaul and the British Royal Navy’s frigate HMS Lancaster responded to the incident, with the Lancaster launching a helicopter.

“The situation de-escalated approximately an hour later when the merchant vessel confirmed the fast-attack craft departed the scene,” the US Navy said. “The merchant ship continued transiting the Strait of Hormuz without further incident.”

The ship was not identified, but ship-tracking data from MarineTraffic showed that Centrofin’s 61,000-dwt Marshall Islands-flag ultramax Venture (built 2016) erratically changed course as it headed through the strait at the time of the incident.

The vessel also matches information given by UK Maritime Trade Operations, a British military operation overseeing traffic in the region.

The bulker resembles images released by the US Navy.

The ship’s registered manager, Trust Bulkers of Athens, has not responded to a request for comment.

The Venture was moored off India on Monday.

Iranian state media and the Revolutionary Guard did not immediately acknowledge the incident.

Three tankers intercepted

It is not clear why the ship would be targeted. Iran usually focuses on tankers with owners or cargoes in some way related to its geopolitical battles with Western powers.

Iranian forces seized and brought into port three overseas tankers in April and May.

The first was Advantage Tankers’ 159,100-dwt suezmax Advantage Sweet (built 2012), which appears to have been targeted in response to the US seizure of Empire Navigation’s 158,600-dwt tanker Suez Rajan (built 2011).

Then there was Smart Tankers’ 309,000-dwt VLCC Niovi (built 2005) and the 9,200-dwt clean product tanker Purity (built 2008).

The French transport ministry’s Equasis database shows the Panama-flag Purity is owned by Sun Ocean Shipping, which is listed at the address of its Hong Kong-based commercial manager, Unicorn Asia.

The database of shipbroker Clarksons, however, shows the vessel is in the control of India’s Coastal Shipping Links.