Boris Johnson in Westminster after winning the Tory leadership (Picture: PA).
Boris Johnson has declined to rule out military intervention in Iran, blaming the country for the attacks on the Saudi oil fields.
The Prime Minister said the UK could attribute blame with a "very high degree of probability" to the Islamic republic.
He told reporters on board the RAF Voyager to New York that he would meet with the Iranian leader at the United Nations General Assembly.
He said he would also raise the case of Nazanin Zaghari-Ratcliffe during discussions on Tuesday afternoon.
The US and Saudi Arabia have already accused Iran of being behind the raids on 14 September on the world's largest oil processor and an oil field, causing a spike in prices. Tehran has issued denials.
But Mr Johnson gave the first attribution of blame from the UK before landing in the US in the early hours of Monday UK-time.
"I can tell you that the UK is attributing responsibility with a very high degree of probability to Iran for the Aramco attacks," he said.
"We think it very likely indeed that Iran was indeed responsible for using both UAVs (unmanned aerial vehicles), both drones and cruise missiles.
"Clearly the difficulty is, how do we organise a global response? What is the way forward?"
Asked if military action was possible, Mr Johnson replied: "We will consider in what way we could be useful if asked and depending on what the exact plan is."
Sanctions also remained on the table.
Mr Johnson is set to meet US President Donald Trump. They have already discussed the need for a "united diplomatic response" to the attacks.
He said: "We will be working with our American friends and our European friends to construct a response that tries to deescalate tensions in the Gulf region."
Iran's Foreign Minister, Javad Zarif, has said the country's President, Hassan Rouhani, will present a proposal at the UN this week for a new security plan for the Gulf.