Iran fired air defence batteries early on Friday morning after reports of explosions near the city of Isfahan, the state-run IRNA news agency reported.

It remained unclear if the country was under attack.

However, tensions remain high in the broader Middle East after Iran’s unprecedented missile-and-drone attack on Israel.

One government official suggested sites may have been targeted by drones.

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

IRNA said the defences fired across several provinces. It did not elaborate on what caused the batteries to fire, though people across the area reported hearing the sounds.

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

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 southeastern 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.”

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 space program, said on the X social media platform that several small” “quadcopter” drones had been shot down.

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

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.