Iran will not disclose cause of mysterious nuclear site fire

An online video and messages purportedly claiming responsibility for a fire that analysts say damaged a centrifuge assembly plant at Iran's underground Natanz nuclear site deepened the mystery Friday around the incident — even as Tehran insisted it knew the cause but would not make it public due to “security reasons.”

The multiple, different claims by a self-described group called the “Cheetahs of the Homeland” included language used by several exiled Iranian opposition organizations, as well as focused almost entirely on Iran's nuclear program, viewed by Israel as a danger to its very existence.

The disparate messages, as well as the fact that Iran experts have never heard of the group before, raised questions about whether Natanz again had faced sabotage by a foreign nation as it had during the Stuxnet computer virus outbreak believed to have been engineered by the U.S. and Israel.

Tehran's reaction so far show Iranian officials are increasingly taking the possibility seriously.

“If it is proven that our country has been attacked by cyberattacks, we will respond,” warned Gen. Gholam Reza Jalali, the head of Iran's military unit in charge of combating sabotage, according to a report late Thursday by the Mizan news agency.

Iranian officials have sought to downplay the fire early Thursday, calling it only an “incident” that affected an “industrial shed.” However, a released photo and video broadcast by Iranian state television of the site showed a two-story brick building with scorch marks and its roof apparently destroyed.

Debris on the ground and a door that looked blown off its hinges suggested an explosion accompanied the blaze.

The fire began around 2 am local time in the northwest corner of the Natanz compound in Iran's central Isfahan province, according to data collected by a US National Oceanic and Atmospheric Administration satellite that tracks fires from space.

Two U.S.-based analysts who spoke to The Associated Press, relying on released pictures and satellite images, identified the affected building as Natanz's new Iran Centrifuge Assembly Center.

Iranian nuclear officials did not respond to a request for comment from the AP on the analysts' findings. However, the semiofficial Tasnim news agency quoted the spokesman of Iran's Supreme National Security Council as saying authorities know the cause of the fire.

“Due to some security considerations, the cause and manner of the accident will be announced at the appropriate time,” Keyvan Khosravi reportedly said, without elaborating.

Before news of the fire became public Thursday, the BBC's Persian service says its journalists received emails from the self-proclaimed “Cheetahs of the Homeland” claiming an attack at Natanz.

A video claimed the group included “soldiers from the heart of regime's security organizations” who wanted to stop Iran from acquiring a nuclear weapon. Iran long has maintained its atomic program is for peaceful purposes. However, the International Atomic Energy Agency has said Iran “carried out activities relevant to the development of a nuclear explosive device” in a “structured program” through the end of 2003.

The video and one written statement also referred to Supreme Leader Ayatollah Ali Khamenei as “zahhak,” a monster in Persian folklore.

But the tone across the messages clashed, with one using terminology often associated with Iran's Mujahedeen-e-Khalq exile group and the video seemingly showing Iran's Shiite theocracy as worse than the rule of Shah Mohammad Reza Pahlavi.

The video also included part of the nationalist song “Ey Iran,” which reformists and opposition groups both sing.

The MEK and supporters of the shah's exiled son Crown Prince Reza Pahlavi did not respond to requests for comment.

The AP received no response to an email sent to one address associated with the “Cheetahs of the Homeland” statements.

The purported group's name, “the Cheetahs of the Homeland,” also struck some as odd, given that the “cheetahs” is a nickname of Iran's national football club.