Iran says US President George Bush has been forced to back down in his tussle with Tehran over its nuclear plans.
President Khatami says talks with Europe are making slow progress
Mr Bush said on Tuesday the notion that the US was preparing to attack Iran to prevent it acquiring nuclear weapons was "simply ridiculous".
Iranian President Mohammad Khatami said the US realised there was no support for its "unacceptable" claims against Iran, so had withdrawn its threats.
Iran denies it is trying to build nuclear weapons.
It says it only wants nuclear power for peaceful, energy-production purposes.
Mr Khatami said: "Sometimes America speaks with a sharp tongue.
"But this threatening language is not practical. They recently realised that such claims are unacceptable and could be problematic even for their own people. This is why they have changed their tone."
Iran says its nuclear activity has solely peaceful motives
"America is inexperienced and ill-informed, and it should not patronise us," he added.
Although Mr Bush dismissed talk of an imminent attack on Iran, he would not rule out a strike at some time, saying all options remained.
On Wednesday, in Germany, he said it was important the world should "speak with one voice" on Iran.
German Chancellor Gerhard Schroeder said: "We absolutely agree that Iran must say no to any kind of nuclear weapons."
The European Union has been taking the lead in diplomatic negotiations with Tehran.
It wants Iran to turn a temporary suspension of uranium enrichment into a permanent halt.
Mr Khatami said on Wednesday: "There are deep differences of opinion between Iran and the Europeans."
He said talks were progressing slowly, but he was "not pessimistic" that the two sides would reach agreement.
However, he once again refused to countenance an indefinite ban on enrichment activity.