The United States and the United Kingdom said on Sunday they believed Iran carried out an attack on an Israeli-managed petroleum product tanker off the coast of Oman on Thursday that killed a Briton and a Romanian. Iran earlier on Sunday denied it was involved in the incident, after it was blamed by Israel.

"Upon review of the available information, we are confident that Iran conducted this attack, which killed two innocent people, using one-way explosive UAVs," U.S. Secretary of State Antony Blinken said in a statement, adding there was "no justification" for the attack.

British Foreign Secretary Dominic Raab said earlier in the day that UK assessments had concluded that it was highly likely that Iran had used one or more drones to carry out the "unlawful and callous" attack.

Israeli Prime Minister Naftali Bennett had accused Iran of being behind the deadly attack. "I declare unequivocally: Iran carried out the attack against the ship," Bennett said at the start of a weekly cabinet meeting.

Iran denied involvement, and foreign ministry spokesman Saeed Khatibzadeh said Israel "must stop such baseless accusations." 

"Iran will not hesitate for a moment to defend its ... interests and national security," he told journalists.

(With input from agencies)