Britain summoned Iran's ambassador on Monday after London and the United States both blamed an attack on an Israeli-managed tanker in Oman last week on Tehran.

"Minister (James) Cleverly reiterated that Iran should immediately cease actions that hazard international peace and security, and reinforced that vessels should be allowed to navigate unreservedly as per international law," the Foreign Office said in a statement.

An Iranian foreign service spokesman said on Monday Iran will react immediately to any threat against its security.

Tehran has denied any association in the attack on Thursday in which two team individuals — a Briton and a Romanian — were killed.

The United States and Britain said on Sunday they would work with their partners to react to the attack on Mercer Street, a Liberian-flagged, Japanese-claimed oil-based commodity tanker managed by Israeli-possessed Zodiac Maritime.

"Iran has no hesitation in ensuring its security and national interests and will react instantly and emphatically to any conceivable adventure," Iranian state TV cited Saeed Khatibzadeh as saying.

Khatibzadeh "emphatically lamented the baseless accusations made by the British foreign secretary against Iran, which was repeated by the U.S. secretary of state in the same setting and contained contradictory, false and provocative accusations", state TV announced.

Earlier, the US and Israel promised to react to a deadly robot attack on the tanker.

Center East enemies Iran and Israel have traded different accusations of transportation attacks lately. Be that as it May, Thursday's strike off the coast of Oman, which Tehran denied carrying out, was quick to kill group individuals — a Romanian and a Briton.

The two fatalities have raised strains in the Gulf at a critical point with Iran preparing to inaugurate another president, and talks with world controls over its 2015 nuclear deal stalled.

"I guarantee you that Israel won't sit quietly by after a negative mark against boats or residents and will react once it discovers the where, the when, and the how," Ram Ben Barak, the head of the Israeli parliament's Foreign Affairs and Defense Committee, told Army Radio on Monday.

Romania said it had summoned the Iranian ambassador, while Britain is sending a team to investigate the attack on the Mercer Street oil-items tanker, presently secured off the United Arab Emirates, its delegate emissary to Israel told Israeli broadcaster, Kan.

"There is no justification for this attack, which follows a pattern of attacks and other combative behavior," US Secretary of State Antony Blinken said in a statement on Sunday. "We are working with our partners to think about our following stages and talking with governments inside the district and past on an appropriate reaction, which will be forthcoming."

He gave no further details of what the reaction may entail. A representative for the US Navy's Fifth Fleet, which is based in the district, declined to remark. The US and its allies created a maritime force in 2019 because of similar attacks to ensure sea lanes in the Middle East.

Blinken said he was "sure" Iran utilized "single direction unstable" drones in Thursday's attack. UK Foreign Secretary Dominic Raab said "at least one" of the unmanned robots may have been associated with the hit.