The eight-member International Maritime Security Construct (IMSC) is still operating in the Middle East Gulf.

The coalition, spearheaded by the US in response to a series of tanker attacks in 2019, held exercises in the waterway on Wednesday with a Bahrain navy ship and two US Coast Guard vessels conducting communication drills and tactical manoeuvres.

“Deterring state-based threats to maritime trade whilst also reassuring the commercial shipping industry remains the core mission of IMSC,” said UK Royal Navy commodore Don Mackinnon, the IMSC's commander.

“Regular training exercises are an essential enabler of that mission, both in terms of enhancing interoperability across and between our coalition members and by contributing to our at-sea presence and continued vigilance.”

The group's operational arm is known as CTF Sentinel and was created after Iran allegedly mined and seized tankers in the Strait of Hormuz. The highest-profile incident was the seizure of the 50,000-dwt tanker Stena Impero (built 2019).

The Stena Bulk tanker was held for two months.

The IMSC patrols the region in an attempt to ensure freedom of navigation alongside the European-backed mission known as European Maritime Awareness in the Strait of Hormuz, or EMASOH.

In November 2020 the IMSC — comprised of Albanaia, Bahrain, Estonia, Lithuania, Saudi Arabia, the United Arab Emirates, the UK and the US — declared success following a drop in what it called “state-sponsored malign activity”.

In 2021, such activity appeared to focus largely on Iran and Israel launching tit-for-tat attacks on each other's commercial ships.

In October, US officials claimed Iran's Islamic Revolutionary Guard Corps navy seized a Vietnam-flag tanker in the Gulf of Oman, while Iran said it fended off an attempt by the US to steal its oil.

Throughout much of 2021, the US and Iran have engaged in periodic talks to revive the 2015 nuclear deal, which would see sanctions lifted on Iran.

The sanctions by some were considered the impetus for the 2019 attacks and their removal is widely considered a positive for tankers.