There was strong support among EU countries for an independent UN investigation and calls for more evidence – with the UK relatively isolated in its support the Trump administration’s line.
One foreign minister invoked the spectre of US misuse of intelligence over Iraq as a reason for scepticism, as representatives of the 28 countries arrived at the council meeting.
The ministers will discuss the incident in the Gulf of Oman over lunch, with Sudan, trade policy with Cuba, and the situation in Venezuela also on the main agenda.
Heiko Maas, the German foreign minister, said the EU states “continue to gather information” while Dutch foreign minister Stef Blok said the Netherlands was “interested in any clarifications that can be made available”.
“We know the findings of the American and the British intelligence services, which assume that you can be almost certain. We are comparing this with our information. I think you have to proceed very, very carefully on this,” Mr Maas said.
Jean Asselborn, Luxembourg’s foreign minister, said: “I believe that the main task of foreign ministers is to avoid war. We have to do that today.”
He added: “I’m convinced, as I was 16 years ago, that you really shouldn’t make the mistake of believing that you can solve a problem in the Middle East with weapons.”
His Finnish counterpart Pekka Haavisto said it was important that EU states have “the full evidence” before reaching any conclusion.
“I support very much the line of the UN Secretary General Mr Guterres, that a proper investigation [to put] all the facts on the table and then we can look what really has happened, who is behind this,” he said.
“I think it’s a very very concerning event but let’s have all the details first.”
Italy’s foreign minister Enzo Moavero said: “We do think that there is room for finding a way for peace and stability in the world.”
Though no hard proof that Iran is behind the attack has been made public, the US has released a video which is claims shows an Iranian patrol boat removing an unexploded mine from one of the tankers.
But asked whether the UK believed Iran was behind the attack, Harriet Baldwin, the foreign office minister representing the UK at the meeting said: “We do now, we over the weekend have come to the conclusion that we are almost certain that this was Iranian action so we stand ready to ensure that this key international waterway remains open to international shipping.”
Ms Baldwin is attending the meeting in place of Jeremy Hunt, who is attending a Tory leadership hustings in Westminster instead.
Mr Hunt on Sunday said the UK was at “great risk” of war with Iran after the incident. The US says it is considering all options, including military action. Hawkish elements within the US administration have long been keen on war with the Middle Eastern state.
The EU has stood by the nuclear deal signed with Iran after Donald Trump renegaded on the agreement signed by his predecessor – while Mr Trump has taken a more aggressive line.