DUBAI/LONDON (REUTERS) - Britain said on Sunday (Aug 1) it believed Iran carried out an attack on an Israeli-managed petroleum product tanker off the coast of Oman last Thursday that killed a Briton and a Romanian, and said it was working with partners on a "concerted response".
Iran earlier on Sunday denied it was involved in the incident, after it was blamed by Israel.
British assessments had concluded that it was highly likely that Iran had used one or more drones to carry out the "unlawful and callous" attack, British Foreign Secretary Dominic Raab said.
"We believe this attack was deliberate, targeted, and a clear violation of international law by Iran," he said on Sunday. "The UK is working with our international partners on a concerted response to this unacceptable attack."
Israeli Prime Minister Naftali Bennett had accused Tehran of "trying to shirk responsibility" for the attack, and called its denial "cowardly".
Iranian Foreign Ministry spokesman Saeed Khatibzadeh told a weekly news conference on Sunday that the "Zionist regime (Israel) has created insecurity, terror and violence ... These accusations about Iran's involvement are condemned by Tehran".
"Such accusations are meant by Israel to divert attention from facts and are baseless," Khatibzadeh said.
The Briton and Romanian were killed in the incident involving the Mercer Street, a Liberian-flagged, Japanese-owned ship managed by Israeli-owned Zodiac Maritime.
The US Navy, which was escorting the tanker with its aircraft carrier USS Ronald Reagan, said on Saturday that early indications "clearly pointed" to a drone attack.
Speaking during a weekly meeting of his cabinet on Sunday, Bennett said: "I declare unequivocally: Iran is the one that carried out the attack on the ship," adding that intelligence supports his claim. "We, in any case, have our own way to relay the message to Iran," Bennett said.
Israel's foreign minister said earlier the incident deserved a harsh response.
There were varying explanations for what happened to the tanker. Zodiac Maritime described the incident as "suspected piracy" and a source at the Oman Maritime Security Center said it was an accident that occurred outside Omani territorial waters.
US and European sources familiar with intelligence reporting said Iran was their leading suspect for the incident.
Iran and Israel have traded accusations of carrying out attacks on each other's vessels in recent months. Tensions have risen in the Gulf region since the United States reimposed sanctions on Iran in 2018 after then-President Donald Trump withdrew Washington from Tehran's 2015 nuclear deal with major powers.