In a written statement, Pentagon spokesman Larry Di Rita said the article by award-winning investigative reporter Seymour Hersh was "so riddled with errors of fundamental fact that the credibility of his entire piece is destroyed."

'US commandos in Iran'

Hersh said secret missions have been going on at least since last summer with the goal of identifying target information for at least three dozen targets in Iran. Those targets "could be destroyed by precision strikes and short-term commando raids," the report said.

'The American task force, aided by the information from Pakistan, has been penetrating eastern Iran from Afghanistan in a hunt for underground installations,' the article said.

'The official added that the government of Pervez Musharraf [Images], the Pakistani President, has won a high price for its co�peration -- American assurance that Pakistan will not have to hand over A Q Khan, known as the father of Pakistan's nuclear bomb, to the IAEA or to any other international authorities for questioning.'

"It's a deal -- a trade-off," the former high-level intelligence official explained. "'Tell us what you know about Iran and we will let your A Q Khan guys go.'

"This is a war against terrorism, and Iraq, is just one campaign," Hersh quoted the official as saying. "The Bush administration is looking at this as a huge war zone. Next, we're going to have the Iranian campaign."

Di Rita's statement cited Hersh's description of a post-election meeting between Secretary of Defense Donald Rumsfeld and the Joint Chiefs of Staff and said it "did not happen."

It also disputed Hersh's assertion that Rumsfeld and two of his key deputies, Stephen Cambone, the undersecretary of defense for intelligence, and Army Lieutenant General William G. [Jerry] Boykin, would be part of the chain of command for the new commando operations.

"The only civilians in the chain of command are the president and the secretary of defense," the statement said. "His assertion is outrageous, and constitutionally specious."

Di Rita said: "Mr. Hersh is building on links created by the soft bigotry of some conspiracy theorists. This reflects poorly onMr. Hersh and the New Yorker. "

Hersh, in an interview with CNN Sunday, described Di Rita's criticisms as "quibbling," saying his information came from "very, very senior" sources.