Iran insists that its nuclear programme is for peaceful purposes
Iran will target "the heart of Israel" and 32 US bases in the Gulf if they launch an attack on Iran, an Iranian official has warned.
The Iranian response would come "before the dust from this attack has settled", Mojtaba Zolnour said.
Mr Zolnour is a representative of Supreme Leader Ayatollah Ali Khamenei to the elite Revolutionary Guards.
His comments come amid fears that Iran could be attacked by the US and Israel over its nuclear programme.
They also followed Iran's testing, earlier this week, of missiles capable of hitting Israel.
Tehran denies Western claims that it is seeking to build a nuclear weapon.
It has repeatedly rejected demands to halt enriching uranium, which can be used as fuel for power plants or material for weapons if refined to a greater degree.
The European Union imposed new sanctions on Iran in June.
But it has offered a package of incentives to persuade Iran to suspend uranium enrichment.
Iran has said it is prepared to negotiate with major world powers, but insisted the talks must address Iran's nuclear rights.