Iran has said it will not accept any changes to its 2015 nuclear deal with world powers after US president Donald Trump vowed to pull out of the accord if European allies do not fix its "terrible flaws".
The Iranian foreign ministry said it “will not accept any change in the deal, neither now nor in future”, adding that it will “not take any action beyond its commitments”.
On Friday, Mr Trump extended the waivers of key economic sanctions that were lifted under the agreement limiting Iran’s nuclear programme.
However, he said he would work with European allies to remove so-called “sunset clauses” that allow Iran to gradually resume advanced nuclear activities in the next decade.
But Britain has insisted the Iran nuclear deal remains “crucial” .
Mr Trump made the threat as he extended waivers of key economic sanctions on Iran, keeping the accord alive for another three months.
A spokeswoman for the British Foreign Office said: "We have noted the White House statement. We will be discussing this with our European partners and with the United States and will respond in detail in due course.
“The UK has a clear position on the Iran nuclear deal: we regard it as a crucial agreement that makes the world a safer place by neutralising the threat of a nuclear-armed Iran.”
The future of the nuclear deal, in which Iran restricted its nuclear programme in exchange for sanctions relief, has become a source of tension between the US and major European countries, including the UK, who back it.
Mr Trump warned that “this is the last chance” as he outlined tough new rules on Iran.
He said: “I am waiving the application of certain nuclear sanctions, but only in order to secure our European allies’ agreement to fix the terrible flaws of the Iran nuclear deal.
“If at any time I judge that such an agreement is not within reach, I will withdraw from the deal immediately. No-one should doubt my word.”