WASHINGTON (Reuters) - The United States has been conducting secret reconnaissance missions inside Iran to help identify potential nuclear, chemical and missile targets, The New Yorker magazine reported Sunday.

The article, by award-winning reporter Seymour Hersh, said the secret missions have been going on at least since last summer with the goal of identifying target information for three dozen or more suspected sites.

Hersh quotes one government consultant with close ties to the Pentagon as saying, "The civilians in the Pentagon want to go into Iran and destroy as much of the military infrastructure as possible."

One former high-level intelligence official told The New Yorker, "This is a war against terrorism, and Iraq is just one campaign. The Bush administration is looking at this as a huge war zone. Next, we're going to have the Iranian campaign."

The White House said Iran is a concern and a threat that needs to be taken seriously. But it disputed the report by Hersh, who last year exposed the extent of prisoner abuse at the Abu Ghraib prison in Iraq.

"We obviously have a concern about Iran. The whole world has a concern about Iran," Dan Bartlett, a top aide to President Bush, told CNN's "Late Edition."...

Pentagon officials on Monday lashed out at a US magazine report which claimed they were preparing for possible strikes on Iran by carrying out secret reconnaissance missions inside the country, saying the article contained "fantastic claims" about programmes that do not exist.

The article, written by veteran investigative reporter Seymour Hersh for The New Yorker magazine, claims that President George W. Bush plans to drastically expand the war on terrorism, and has already signed executive orders authorising secret commando operations against terrorist targets in as many as ten middle eastern and south Asian nations, including Iran.

The Iranian operation, which the article claims has been underway since last summer, intends to identify as many three dozen Iranian military or nuclear sites for US missile attacks or commando raids.

Lawrence DiRita, the Pentagon's chief spokesman, said in a statement on Monday that many of the facts upon which the story is based are inaccurate. Neither he nor Dan Bartlett, the White House spokesman, commented directly on the commando operations claim, however.

"Mr Hirsch's sources feed him with rumour, innuendo, and assertions about meetings that never happened, programmes that do not exist, and statements by officials that were never made," the Mr DiRita said.

It is rare for the Pentagon to issue such a long and detailed response to a single news account; Mr DiRita's two-page statement includes four specific refutations of claims made in the piece, including an alleged post-election meeting between Donald Rumsfeld and the joint chiefs of staff in which the defence secretary claimed the 2004 US election was a referendum on aggressive action in the Middle East...