"If the US attacks, Israel will undoubtedly be a participant," Ali Shamkhani told Al Mayadeen.
He has also stated Tehran would not remove its stored nuclear materials but is open to reducing enrichment from 60% to 20%.
Earlier, Iranian media reported that Iran and the United States may start negotiations in the coming days, with Iranian Foreign Minister Abbas Araghchi and US special envoy Steve Witkoff likely acting as negotiators.
In January, US President Donald Trump said a "massive armada" was heading towards Iran, adding that he hoped Tehran would agree to negotiate and sign a "fair and equitable" deal involving a complete abandonment of nuclear weapons. The president warned that if no agreement on Iran's nuclear program was reached, any future US strike on the country would be "far worse" than the previous ones.