Iran has criticised Defence Secretary Liam Fox for saying Tehran may be capable of developing a nuclear weapon by next year.
Dr Fox’s remarks go “against reality” and aim to create an “environment detrimental to Iran”, said foreign ministry spokesman Ramin Mehmanparast.
In talks last month, the United States, Britain, France, Germany, Russia and China failed to persuade Iran to open its atomic programme to more scrutiny.
Tehran claims its nuclear programme is limited to peaceful purposes, such as electricity production.
The US and its allies insist Iran is working on the covert development of nuclear weapons.
Dr Fox told the House of Commons on Monday that it is “entirely possible” that Iran might develop a nuclear weapon by next year.
He said Tehran was continuing to pursue uranium enrichment as well as the construction of a heavy water reactor, both of which had “military potential”.
And he cautioned the West not to be “caught out” and assume “things are more rosy than they are”, as had happened with North Korea.