Iran fired air defences at a major air base and a nuclear site near the central city of Isfahan after spotting drones early on Friday morning, raising fears of a possible Israeli strike in retaliation for Tehran’s unprecedented drone-and-missile assault on the country earlier this week.

It was unclear if the country came under attack, as no Iranian official has directly acknowledged the possibility and Israel’s military did not respond to a request for comment.

However, tensions have been high since the Saturday assault on Israel amid its war on Hamas in the Gaza Strip and its own strikes targeting Iran in Syria.

Speaking at the G7 meeting in Capri, Italian foreign minister Antonio Tajani said the US received “last-minute” information from Israel about the attack on Isfahan.

US officials declined to comment early on Friday, but American broadcast networks quoting unnamed US officials said Israel carried out the attack. The New York Times quoted anonymous Israeli officials also claiming the assault.

Israeli politicians also made comments hinting that the country had launched an attack.

Air defence batteries fired in several provinces over reports of drones being in the air, state television reported. Iranian army commander Gen Abdolrahim Mousavi said crews targeted several flying objects.

“The explosion this morning in the sky of Isfahan was related to the shooting of air defense systems at a suspicious object that did not cause any damage,” Gen Mousavi said.

Others suggested the drones may be so-called quadcopters – small, four-rotor drones that are commercially available.

In particular, Iranian media said air defences fired at a major air base in Isfahan, which long has been home to Iran’s fleet of American-made F-14 Tomcats — purchased before the 1979 Islamic Revolution.

Iran’s Foreign Minister Hossein Amir-Abdollahian
Iran’s Foreign Minister Hossein Amir-Abdollahian arrives for a meeting with United Nations Secretary-General Antonio Guterres at United Nations headquarters on Thursday (AP)

The Israeli military did not immediately respond to a request for comment.

Iranian state television says nuclear facilities near Isfahan are “fully safe” after air defence batteries fired in the area.

The semi-official Fars and Tasnim news agencies reported the sound of blasts without giving a cause.

State television acknowledges a “loud noise” in the area.

Tasnim later published a video from one of its reporters, who said he was in the south-eastern Zerdenjan area of Isfahan, near its “nuclear energy mountain”.

The footage showed two different anti-aircraft gun positions, and its details corresponded with known features of the site of Iran’s Uranium Conversion Facility at Isfahan.

“At 4.45, we heard gunshots. There was nothing going on,” he said.

“It was the air defence, these guys that you’re watching, and over there too.”

Iranian drone wreckage
Israeli military spokesperson, Rear Adm Daniel Hagari, with one of the Iranian ballistic missiles Israel intercepted over the weekend (AP)

Dubai-based carriers Emirates and FlyDubai began diverting around western Iran at about 4:30am local time.

They did not explain, though local warnings to aviators suggested the airspace may have been closed.

Iran later announced it grounded commercial flights in Tehran and across areas of its western and central regions.

Loudspeakers informed customers of the incident at Imam Khomeini International Airport in Tehran, online videos purported to show.

Iranian state television began a scrolling, on-screen alert acknowledging a “loud noise” near Isfahan, without immediately elaborating.

Hossein Dalirian, a spokesman for Iran’s civilian cyberspace programme, said on the X social media platform that several small” “quadcopter” drones had been shot down.

Iron Dome
A battery of Israel’s Iron Dome defence missile system in Ashkelon, southern Israel (AP)

It was not immediately clear where that happened or if it was part of the ongoing incident in Iran.

Around the time of the incident in Iran, Israeli warplanes flying over Syria’s southern province of Daraa struck a military radar for government forces after it spotted the fighter jets, according to the Britain-based Syrian Observatory for Human Rights, an opposition war monitor. It was not clear if there were casualties, the Observatory said.

That area of Syria is directly west of Isfahan, around 930 miles away, and east of Israel.

Meanwhile, in Iraq, where a number of Iranian-backed militias are based, residents of Baghdad reported hearing sounds of explosions, but the source of the noise was not immediately clear.

Separately, the US and Britain announced that they were imposing a new round of sanctions on Iran. The moves came as European Union leaders meeting in Brussels vowed to ramp up sanctions on Iran to target its drone and missile deliveries to proxies in Gaza, Yemen and Lebanon.

The US sanctions target individuals and entities that produce engines that power drones and are involved in steel production. The latest British measures target several Iranian military organizations, individuals and entities involved in Iran’s drone and ballistic missile industries.