Britain believes Iran was responsible for the recent attack on Saudi oil facilities and will work with the US and European allies on a joint response, Prime Minister Boris Johnson says.

The US and Saudi Arabia have already blamed Iran for the September 14 strikes that initially halved Saudi oil output. Yemen’s Iran-aligned Houthi movement has claimed responsibility.

“The UK is attributing responsibility with a very high degree of probability to Iran for the Aramco attacks. We think it very likely indeed that Iran was indeed responsible,” Mr Johnson said while flying to the United Nations General Assembly in New York.

“We will be working with our American friends and our European friends to construct a response that tries to de-escalate tensions in the Gulf region.”

A British government official said the Houthis’ claim of responsibility was “implausible”, with the scale, sophistication and range of the attack inconsistent with their capabilities.

“It is implausible it wouldn’t have been authorised by the Iranian government,” the official said.

Asked whether Britain would rule out military action, Mr Johnson said it would be closely watching a proposal by the US to do more to help defend Saudi Arabia.

“Clearly if we are asked, either by the Saudis or by the Americans, to have a role then we will consider in what way we could be useful,” he said.

Mr Johnson said he would discuss Iran’s actions in the region with President Hassan Rouhani at the UN meeting. He will also push for the release of several dual national Iranians who he said were being held “illegally and unfairly”.

-AAP