Iranian air defences have been activated after an apparent Israeli drone attack on a major air base near the central city of Isfahan.

The strike early on Friday morning came just days after Tehran’s unprecedented drone and missile assault on Israel.

No Iranian official directly acknowledged the possibility that Israel had attacked, and the Israeli military did not respond to a request for comment.

However, regional tensions have been high since last Saturday’s 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 secretary of state Antony Blinken did not dispute that, but said: “We were not involved in any offensive operations.”

The apparent attack came on Iranian Supreme Leader Ayatollah Ali Khamenei’s 85th birthday. 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 General Abdolrahim Mousavi said crews had targeted several flying objects.

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

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

Authorities 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.

The Tasnim news agency 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 details of the video corresponded with known features of the site of Iran’s Uranium Conversion Facility at Isfahan.

The facility at Isfahan operates three small Chinese-supplied research reactors, as well as handling fuel production and other activities for Iran’s civilian nuclear programme.

Isfahan also is home to sites associated with Iran’s nuclear programme, including its underground Natanz enrichment site, which has been repeatedly targeted by suspected Israeli sabotage attacks.

State television described all atomic sites in the area as “fully safe”. The United Nations’ nuclear watchdog, the International Atomic Energy Agency (IAEA), also said “there is no damage to Iran’s nuclear sites” after the incident.

The IAEA “continues to call for extreme restraint from everybody and reiterates that nuclear facilities should never be a target in military conflicts”, the agency said.

Around the time of the incident in Iran, Syria’s state-run SANA news agency quoted a military statement saying Israel carried out a missile strike targeting an air defence unit in its south and causing material damage.

The UK-based Syrian Observatory for Human Rights, an opposition war monitor, said the strike hit a military radar for government forces. It was not clear if there were casualties, the Observatory said.

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

The incident on Friday in Iran also sparked concerns about the conflict again escalating across the seas of the Middle East, which have been seeing attacks by the Iranian-backed Houthi rebels of Yemen on shipping over the war in Gaza.

The United Kingdom Maritime Trade Operations centre warned ships in the region that they could see increased drone activity in the skies.

Meanwhile, Iranian state-run media sought to downplay the apparent drone incident after the fact, airing footage of an otherwise-peaceful Isfahan morning.