Tehran said no decision has been made on a peace deal with the United States after US President Donald Trump claimed an initial agreement aimed at ending the war in Iran had been reached.

Speaking to reporters from the White House on Thursday, Trump said: "We just made a great settlement of the war with Iran and we're going to be subject to finalisation of documents, which should get done over the next few days".

Iran's foreign ministry spokesman Esmaeil Baqaei said Tehran "had not reached a final conclusion on the agreement".

"Most of the text of the agreement was finalized, but the problem began when the US side made new demands and changed its positions," Baqaei added.

It comes after Trump said he was calling off strikes on Iran on Thursday as talks over a deal advanced.