An explosion rocked the western Iranian city of Isfahan on Monday, the semi-official Fars news agency reported, adding that the blast was heard in several parts of the city.

According to reports, frightened residents called the fire department after the blast, forcing the city authorities to admit there had been an explosion.Residents reported that their windows shook from the explosion's force.

Open gallery view Original report of blast in Iranian city of Isfahan as appeared on Fars website, Nov. 28, 2011.

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Speaking to an Iranian news website, the government of Isfahan said that the explosion occurred as a result of a military drill, denying reports that the blast was somehow related to the nearby nuclear facility.

"There is no such thing, the blast was entirely from the military maneuver," the Iranian official said.

The Isfahan uranium conversion plant operates under the supervision of the International Atomic Energy Agency, and is frequented by its inspectors and surveyed by cameras that broadcast to the IAEA headquarters in Vienna.

Thus, had the explosion occurred at the nuclear site, the UN's nuclear watchdog would have known of the incident.

Speaking with Fars news agency earlier Monday, Isfahans deputy mayor initially confirmed the reports and said the authorities are investigating the matter. However, after the incident was reported in Israel, the report was taken off the Fars website.

It seems that city authorities and the Iranian government were embarrassed by the reports of a blasts, releasing contradictory versions of the alleged events. One example is a statement given by the same deputy mayor to the Mehr news agency, saying he had no reports of an explosion.

Another confirmation came from the head of the city's judiciary, who said an explosion-like sound was heard. Meanwhile, the Mehr news agency reported there has been a blast at a petrol station near the city. Another report pointed to a training accident.

The reported incident occurred about two weeks after Gen. Hasan Tehrani Moghaddam was killed together with 20 other Guard members Nov. 12 at a military site outside Bidganeh village, 40 kilometers southwest of Tehran.

The Revolutionary Guard said the accidental explosion occurred while military personnel were transporting munitions.

It should be noted that Iran operates a uranium conversion plant near Isfahan, one with an important function in the chain of Iran's nuclear program.

It first went into operation in 2004, taking uranium from mines and producing uranium fluoride gas, which then feeds the centrifuges that enrich the uranium.

Since 2004, thousands of kilograms of uranium flouride gas were stockpiled at Isfahan and subsequently sent to the enrichment plant in Natanz.

Commenting on the report of an explosion in Isfahan, U.S. State Department Spokesman Mark Toner said: "We don't have any information at this time other than what we've seen in the press as well. But certainly we're looking into it."

"As you know, we're somewhat limited in our ability to glean information on the ground there, but we're certainly looking into it," Toner added.

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Earlier Monday, a top Israeli security official said that the recent explosion that rocked an Iranian missile base near Tehran could delay or stop further Iranian surface-to-surface missile development.

The official added, however that the Iranian nuclear program was continuing to gain ground, despite considerable international pressure and attempts to destabilize the Iranian regime.

קראו כתבה זו בעברית: איראן: פיצוץ עז החריד את העיר איספהאן