An explosion deep within Iran's Fordow nuclear facility has destroyed much of the installation and trapped about 240 personnel deep underground, according to a former intelligence officer of the Islamic regime.

The previously secret nuclear site has become a center for Iran's nuclear activity because of the 2,700 centrifuges enriching uranium to the 20-percent level. A further enrichment to weapons grade would take only weeks, experts say.

The level of enrichment has been a major concern to Israeli officials, and Prime Minister Benjamin Netanyahu repeatedly has warned about the 20-percent enriched stockpile.

The explosion occurred Monday, the day before Israeli elections weakened Netanyahu's political control.

Iran, to avoid alarm, had converted part of the stockpile to fuel plates for use in the Tehran Research Reactor. However, days after the recent failed talks with the International Atomic Energy Agency, Iranian officials announced the enrichment process will not stop even "for a moment."

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The regime's uranium enrichment process takes place at two known sites: the Natanz facility with more than 10,000 centrifuges and Fordow with more than 2,700. The regime currently has enough low-grade (3.5 percent) uranium stockpiled for six nuclear bombs if further enriched.

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However, more time is needed for conversion of the low-grade uranium than what would be needed for a stockpile at 20 percent. It takes 225 kilograms of enriched uranium at the 20-percent level to further enrich to the 90-percent level for one nuclear bomb.

According to a source in the security forces protecting Fordow, an explosion on Monday at 11:30 a.m. Tehran time rocked the site, which is buried deep under a mountain and immune not only to airstrikes but to most bunker-buster bombs. The report of the blast came via Hamidreza Zakeri, formerly with the Islamic regime's Ministry of Intelligence and National Security,

The blast shook facilities within a radius of three miles. Security forces have enforced a no-traffic radius of 15 miles, and the Tehran-Qom highway was shut down for several hours after the blast, the source said. As of Wednesday afternoon, rescue workers had failed to reach the trapped personnel.

The site, about 300 feet under a mountain, had two elevators which now are out of commission. One elevator descended about 240 feet and was used to reach centrifuge chambers. The other went to the bottom to carry heavy equipment and transfer uranium hexafluoride. One emergency staircase reaches the bottom of the site and another one was not complete. The source said the emergency exit southwest of the site is unreachable.

The regime believes the blast was sabotage and the explosives could have reached the area disguised as equipment or in the uranium hexafluoride stock transferred to the site, the source said. The explosion occurred at the third centrifuge chambers, with the high-grade enriched uranium reserves below them.

The information was passed on to U.S. officials but has not been verified or denied by the regime or other sources within the regime.

Though the news of the explosion has not been independently verified, other sources previously have provided WND with information on plans for covert operations against Iran's nuclear facilities as an option before going to war. The hope is to avoid a larger-scale conflict. Israel, the U.S. and other allies already have concluded the Islamic regime has crossed its red line in its quest for nuclear weapons, other sources have said.

However, this information was not revealed for security reasons until several days ago when sources said the regime's intelligence agency, through an alleged spy in the Israeli intelligence agency Mossad, had learned of the decision to conduct sabotage on Iran's nuclear sites on a much larger scale than before.

As reported, President Mahmoud Ahmadinejad called an urgent meeting Tuesday with the intelligence minister, the head of Iran's Atomic Energy Organization and other officials to discuss the threat, and now it's clear the meeting included the sabotage at Fordow.

Several Iranian nuclear scientists have been assassinated in recent years. Last year, saboteurs struck the power supply to the Fordow facility, temporarily disrupting production. And a computer worm called Stuxnet, believed to have originated in the U.S., set Iran's plans for nuclear weapons back substantially.

The 5+1 (the United States, Russia, China, Britain, France and Germany) hope to resume talks with Iran over its illicit nuclear program. The talks ended last year after regime officials refused to negotiate.

Sources in the Islamic regime previously have revealed exclusively to WND the existence of: