As Israel launched a missile strike on Iran Friday, Tehran claimed to have activated its air defence system and that it shot down several drones.

Israel launched a strike against Iran in retaliation for its weekend attack, said US officials, though media from both countries appeared to downplay the severity of the incident.

Iran activated its air defence system over several cities, state media reported, soon after the country's official broadcaster said explosions were heard near Isfahan, Iran's third-biggest city.

Several Iranian nuclear sites are located in Isfahan province, including Natanz, the centerpiece of Iran's uranium enrichment program.

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

The attack came just hours after Iranian Foreign Minister Hossein Amir-Abdollahian told CNN in an interview that if Israel takes any further military action against it would be “immediate and at a maximum level."

The sound of explosions was heard around 4:00 am in the northern and eastern regions of Isfahan province, Mehr News Agency reported.

Though some media reports said that missiles had been fired, Iran said that they had shot down several drones but there had been "no missile attack for now".

Several drones "have been successfully shot down by the country's air defence, there are no reports of a missile attack for now," Iran's space agency spokesman Hossein Dalirian said on X.

Earlier, Israel Defence Forces Chief of Staff Lt. Gen. Herzi Halevi warned that Iran's attack on his country will be 'met with a response'.

He made the remarks while visiting Nevatim Airbase in Israel where four Iranian ballistic missiles hit on April 13.

“Iran wanted to harm the strategic capabilities of the State of Israel — that is something that had not happened before. We were prepared for the ‘Iron Shield’ operation — preparation that brought Iran to also encounter aerial superiority,” he was quoted as saying by The Times of Israel.

“We are looking ahead, we are considering our steps, and this launch of so many missiles, cruise missiles, and UAVs into the territory of the State of Israel will be met with a response,” he added.