Closing the strait would prevent Iran's energy exports from leaving the country's waters. File Image / Pixabay

Iran's authorities have not made any formal announcement of the closure of the Strait of Hormuz in response to US and Israeli strikes on the country, according to a British government agency monitoring maritime security in the region.

Ships operating in the region are receiving communications claiming the strait has been closed, but no formal notification has been made, the UK Maritime Trade Operations agency said in a social media post on Sunday.

"Claims regarding the closure of the Strait of Hormuz continue to circulate via open-source reporting and VHF communications," the agency said.

"No official closure of the Strait of Hormuz has been formally communicated to the maritime industry through recognised maritime safety channels, including NAVAREA warnings or IMO-recognised Maritime Safety Information broadcasts.

"VHF communications indicating transit restrictions do not constitute a legally recognised suspension of transit passage under international maritime law."

The US and Israel attacked a series of military facilities in Iran on Saturday, killing Ayatollah Ali Khamenei and several other senior government figures. Iran responded with strikes on US bases and other targets across the Middle East.

The Strait of Hormuz is a key chokepoint for the global shipping industry, particularly for tanker traffic in the Middle East, and closing the strait to commercial shipping has been a longstanding threat from Iran on how it might respond to war. While Iran can quickly discourage commercial shipping from operating in the area by threatening attacks, there is significant doubt among experts over whether it could practically prevent all traffic through the area on a long-term basis in the face of US naval opposition to such a move.

Closing the strait would prevent Iran's energy exports from leaving the country's waters, which would deliver the country a financial crisis if continued over a prolonged period.

But for now, warnings from insurers over cancelled policies or sharply higher costs for ships operating in the area may be enough to stop the majority of vessels from transiting the strait.

As of Sunday morning traffic is still moving through the Strait of Hormuz, albeit at a significantly reduced rate. Several leading shipping companies including Hapag-Lloyd and CMA CGM are avoiding transits through the waterway.

Electronic interference in the region is also making it less safe for commercial shipping, as well as making it harder to track vessel movements via AIS data.