"The foreign source of the incident has not been confirmed. We have not received any external attack, and the discussion leans more towards infiltration than attack," the Iranian official said on condition of anonymity.

The International Atomic Energy Agency (IAEA) said that there has been no damage to Iranian nuclear sites following explosions Friday in the centre of Iran that have been described as Israeli revenge attacks, .

"IAEA can confirm that there is no damage to Iran’s nuclear sites," the Vienna-based agency said on X, adding that it was closely monitoring the situation.

The agency called for "extreme restraint from everybody" and added that "nuclear facilities should never be a target in military conflicts". 

Iran's Fars news agency reported "three explosions" were heard near Qahjavarestan, near Isfahan airport and the 8th Shekari army airbase.

Nuclear facilities in Isfahan were reported to be "completely secure", Iran's Tasnim news agency said.

Israel had previously warned it would hit back after Iran fired hundreds of missiles and drones at Israel almost a week ago, in retaliation for a deadly strike -- which Tehran blamed on its foe -- that levelled Iran's consular annex at its embassy in Syria.

IAEA chief Rafael Grossi had said Monday that Iran had closed its nuclear installations for security reasons.

France, meanwhile is calling for de-escalation in the Middle-East crisis, Deputy French Foreign Minister Jean-Noel Barrot said on Friday, responding to reports that Israel launched an air attack on Iranian soil earlier that day.

"All I can say is that France's position is to call on all actors for de-escalation and restraint," Barrot told Sud Radio.