The United States will help investigate a deadly attack on an oil tanker managed by a prominent Israeli billionaire, the State Department said Saturday.

The MT Mercer Street was struck Thursday off the coast of Oman in an incident Israel has blamed on arch-foe Iran. 

Two crew members were killed in what the US military and the vessel's operator said appeared to be a drone strike, with US naval forces coming to the aid of the ship in the attack's aftermath.

US Secretary of State Antony Blinken spoke with his Israeli counterpart Yair Lapid and both men agreed to work with other allies "to investigate the facts, provide support, and consider the appropriate next steps," according to a State Department statement.

Vessel operator Zodiac Maritime, owned by Israeli billionaire Eyal Ofer, said a British security guard and a Romanian crew member were killed in the attack. 

On Friday, Lapid said he had ordered the nation's diplomats to push for UN action against "Iranian terrorism".

"I've instructed the embassies in Washington, London and the UN to work with their interlocutors in government and the relevant delegations in the UN headquarters in New York," Lapid said on Twitter.

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