TEHRAN -- Iran's nuclear chief said on Friday that no radiation leak "of concern" had occurred following Israel's airstrike on the Natanz nuclear facility in central Isfahan province.

Mohammad Eslami, head of the Atomic Energy Organization of Iran (AEOI), told state broadcaster IRIB that the attack had targeted the site repeatedly to inflict maximum damage, but caused only limited surface-level equipment losses and no casualties.

"We had no radiation leak that could worry people, and there was no significant harm in this regard," Eslami said. "We are continuing to assess the full extent of the damage."

Earlier on Friday, Israel launched airstrikes on Tehran and several other Iranian cities, killing at least 78 people and wounding 329 in the capital alone, according to the semi-official Fars news agency.

Among those reported killed in Tehran were top military officials, including the Chief of Staff of the Iranian Armed Forces Mohammad Bagheri, Islamic Revolutionary Guard Corps (IRGC) Commander Hossein Salami, Khatam al-Anbiya Central Headquarters Commander Gholam-Ali Rashid, and IRGC Aerospace Division Commander Amir Ali Hajizadeh.

In response, Iran's Supreme Leader Ali Khamenei vowed retaliation, warning that Israel must "await a harsh punishment" for what he called a "crime" against the country.