Iran yesterday vowed to respond to any "adventurism", its foreign ministry said, after the US and Britain joined Israel in blaming it for a deadly tanker attack, claims Tehran denies.

The MT Mercer Street, managed by prominent Israeli billionaire Eyal Ofer, was attacked on Thursday off Oman.

A British security guard and a Romanian crew member were killed in what the United States, Britain and the vessel's operator Zodiac Maritime said appeared to be a drone strike.

British Prime Minister Boris Johnson said yesterday Iran should face consequences.

Analysts said the attack bore all the hallmarks of tit-for-tat exchanges in the "shadow war" between Israel and Iran, in which vessels linked to each nation have been targeted in waters around the Gulf.

Israel blamed Iran for the attack, accusations rejected by Tehran, with Iran's foreign ministry spokesman Saeed Khatibzadeh saying Sunday that Israel "must stop such baseless accusations".

The US and Britain on Sunday also then blamed Iran for the attack, with Washington vowing an "appropriate response".

Iran "will not hesitate to protect its security and national interests, and will immediately and decisively respond to any possible adventurism," ministry spokesman Khatibzadeh said in a statement.

He dismissed the US and Britain's statements as "contradictory", and said "if they have any evidence to support their baseless claims, they should provide them".

Khatibzadeh also accused them of effectively supporting "terrorist attacks against and sabotage of Iran's commercial ships" through their "silence".

Yesterday, Britain summoned Iran's ambassador to London in response to what it called "the unlawful attack", a government statement read.

"Iran must immediately cease actions that risk international peace and security," it added, saying that "vessels must be allowed to navigate freely in accordance with international law".

Iran's foreign ministry also summoned the British charge d'affaires to "protest remarks" made by the UK's foreign secretary, state news agency IRNA reported.

He was told that "these hasty, contradictory, and baseless remarks are rejected and strongly condemned," the agency said.