Foreign Secretary Dominic Raab has welcomed both NATO and the European Commission’s condemnation of the deadly attack on an oil tanker off the coast of Oman.
The UK, US and Israel have blamed Iran for the attack, which killed two people – a Briton and a Romanian.
On Tuesday, NATO called on Iran to “respect its international obligations”, while the EU Commission said they oppose “any action that would be detrimental to peace and stability”.
The Commission called the incident “unacceptable” but said the exact circumstances surrounding it “have to be clarified”.
Posting on social media, Mr Raab said: “I welcome NATO joining the UK and international partners in condemning the unlawful attack on MV Mercer Street.
“We believe this was a deliberate, targeted attack by Iran – it must end its destabilising actions immediately.”
I welcome @NATO joining the UK 🇬🇧 and international partners in condemning the unlawful attack on MV Mercer Street.
We believe this was a deliberate, targeted attack by Iran – it must end its destabilising actions immediately. https://t.co/aZGfjmgk4u
Reports suggest explosive drones were flown into the MV Mercer Street tanker during the attack, which happened on 29 July.
According to Eikon’s ship tracking, the Mercer Street was headed to Fujairah, a bunkering port and oil terminal in the United Arab Emirates, from Dar es Salaam in Tanzania.
The tanker is operated by Zodiac Maritime, which is based in London and owned by Israeli billionaire Eyal Ofer.
Releasing a statement on Tuesday, a NATO spokesperson said: “We join allies in strongly condemning the recent fatal attack on the MV Mercer Street off the coast of Oman, and express our condolences to Romania and the United Kingdom for the losses they have suffered.
“Freedom of navigation is vital for all Nato allies, and must be upheld in accordance with international law.
“The United Kingdom, the United States, and Romania have concluded that Iran is highly likely responsible for this incident. Allies remain concerned by Iran’s destabilising actions in the region, and call on Tehran to respect its international obligations.”
European Commission spokeswoman Nabila Massrali told reporters: “Of course we condemn the attack on the oil tanker which took place off the island of Masirah in Oman.
“A British citizen and a Romanian were killed and we would like to extend our sympathy to their friends and family.
“The exact circumstances of this attack have to be clarified and we take note of investigations carried out by the United States, the UK and Israel – this is an action that was against freedom of navigation in this area, and of course unacceptable.
“We oppose any action that would be detrimental to peace and stability in this area and the EU will continue to follow developments closely.”
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On Sunday, Mr Raab accused Iran of carrying out a “deliberate, targeted” assault which constituted “a clear violation of international law”.
US Secretary of State Anthony Blinken said he was considering “next steps” with the UK and other allies, with “an appropriate response… forthcoming”.
Meanwhile, the head of the British armed forces, General Sir Nick Carter, held discussions with his Israeli counterpart at the weekend.
The government held a Cobra emergency meeting at the level of officials over the weekend in a sign of the serious focus on the tanker attack and how to respond, Sky News understands.
There has not yet been a Cobra attended by ministers, which is what happens in the gravest of crises.
Earlier this week, Israeli foreign minister Yair Lapid blamed “Iranian terrorism” for the attack.
Iran has not yet commented on the allegations.
Lisa Nandy, Labour’s shadow foreign secretary, said the UK government needs to take a hard line with Tehran.
She said: “The prime minister must make it clear to the incoming Iranian president that lawless actions will carry costs. This is the moment where Britain must show we are resolute in our determination to end this pattern of behaviour.
“The breakdown of a clear strategy to deal with Iran has not served the UK or our allies well in recent years. The foreign secretary must now make it a priority to pursue coordinated international efforts to tackle these actions by the Iranian government.”
The incident has sparked concern that tensions are increasing in the region.
A UK source said crew members reported being targeted by “some sort of drone” on Thursday in the Arabian Sea before communications with the ship were lost.
If a drone attack is confirmed it would raise speculation about a possible link to a government or some kind of proxy group.
Iran in the past has repeatedly been accused of targeting tankers in the Gulf.