a sound similar to an explosion was heard from Isfahan, according to Iran's ISNA news agency.

"In the afternoon, there was a noise like an explosion, but we don't have any information from security forces on the source of the noise," Gholamreza Ansari was quoted as saying.

The Mehr news agency said other unidentified Iranian news media had reported that the blast took place at a petrol station at a town near Isfahan city.

Isfahan is home to nuclear experimental reactors, and also a uranium enrichment facility for producing nuclear fuel.

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two weeks after a massive explosion west of Tehran which killed 17 troops, including an IRGC officer responsible for the development of some of Iran's most advanced weapons.

The cause of the explosion was unknown and Iran claimed it occurred when soldiers were moving explosives between bases. There was some speculation on Sunday that sabotage had caused the blast and Israel was involved with the assistance of local Iranian opposition groups.

It was not the first time that mysterious explosions struck in Iran. In recent years, a number of scientists have been killed in car bombings and dozens of IRGC officers have also been killed in various plane crashes.