Boris Johnson has called for a new nuclear deal with Iran, signalling a major shift in the UK’s position.
The Prime Minister pushed for a new negotiation beyond the 2015 agreement between the Middle Eastern country and other world powers.
Mr Johnson’s remarks on Monday come after he earlier blamed Iran for recent attacks on Saudi Arabian oil facilities.
"How do we respond to what the Iranians plainly did? What the UK is doing is trying to bring people together and de-escalate tensions," he told Sky News as world leaders gathered at the United Nations in New York.
"Whatever your objections to the old nuclear deal with Iran, it's time now to move forward and do a new deal."
Donald Trump praised Mr Johnson for floating the idea, saying: “That’s why he’s a winner and that’s why he’s going to be successful in the UK.”
A government spokesman later said that Mr Johnson did still support the 2015 pact but wanted to find a way to bring Tehran into compliance.
European leaders have struggled to dampen a brewing confrontation between Tehran and Washington since the US President pulled out more than a year ago from a deal that assures Iran access to world trade in return for curbs on its nuclear programme.
The US re-imposed sanctions on Iran last year and tightened them sharply this year.
Iran has responded by breaching some of the limits on nuclear material in the deal and has set an October deadline to reduce its nuclear commitments further unless the pact is salvaged.
The European powers party to the deal - France, Britain and Germany - have until now remained united despite pressure from Washington.
But an attack on Saudi Arabia's oil facilities on September 14, which Washington has blamed on Iran, is testing that unity.
Iran denies responsibility for the attack on Saudi Arabia.
Yemen's Iran-aligned Houthi movement, which has been battling a Saudi-led military coalition that includes the UAE, has claimed responsibility for the strikes.
Mr Johnson was already at odds on Monday morning with French President Emmanuel Macron over who to blame for the attack, blaming Tehran directly.
Those words were in stark contrast to Mr Macron, who has been extremely cautious not to point the finger directly at Iran, fearing that it could increase tensions.
Mr Macron has led a European push over the summer to find a compromise between Washington and Tehran and wants to use the UN meeting as an opportunity to revive diplomacy.
His efforts have stalled in recent weeks, with Iran reducing its commitments to the nuclear accord, and the US refusing to ease sanctions that have strangled its oil exports, a mainstay of the Iranian economy.
Agencies contributed to this report
