Brigadier-General Muhammad Ali Jafari told the Shargh newspaper on Wednesday that Tehran "will counter any stupid action by Israel and its master with firmness and in an astonishing way".
The commander of the Revolutionary Guards' ground forces said Iran now had the capacity to defeat any invader within months.
"We pushed the Baathist enemy from our country within one and a half years," he said, referring to the opening campaigns of the 1980-88 war with Iraq.
"With the experience and skills from that war and in the case of any invasion, the invaders will be defeated in less than one and a half months," Jafari said.
US officials have in recent days hardened their tone against the Islamic republic, which US President George Bush had earlier lumped into an "axis of evil" with Iraq and North Korea.
Last Monday, Bush said he could not rule out using force if Tehran failed to rein in its nuclear plans, and US Vice-President Dick Cheney said Iran was "right at the top of the list" of global trouble spots.
Cheney also warned that Israel might launch a pre-emptive strike on its own to shut down Iran's nuclear programme.
"We would love American commandos to enter Iran ... because they are chicks. Our eagles will catch them in no time. The Americans are stupid, but not as stupid as that"
Iranian intelligence minister
But Iranian Intelligence Minister Ali Yunusi responded to both Bush and Cheney's remarks in a broadcast on Iran's Channel two.
"This is a psychological war that they have started in order to influence the talks on the nuclear issue.
"They think that this way they can force us to make the concessions they want. Otherwise, they do not have the ability to carry out their military threat," he told Aljazeera.net.
When asked if he believed claims made by US journalist Seymour Hersh that US commandos were operating inside Iran, Yunusi rejected the idea.
"We would love American commandos to enter Iran ... because they are chicks. Our eagles will catch them in no time. The Americans are stupid, but not as stupid as that."