Iranian state-run news agency IRNA claimed that air defense batteries were fired early Friday morning (Apr. 19) after reports of explosions near a major airbase in the city of Isfahan. 

However, it remained unclear if the country was under attack after a senior US official revealed that Israel made a retaliatory strike after Iran's unprecedented missile and drone attack on Israel, the Associated Press reported. 

One government official suggested drones might have targeted sites. 

Israeli military officials did not immediately respond to reporters' requests for comment.

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

The news agency said that air defenses fired at a major airbase in Isfahan, where the country's F-14 Tomcats are located. The fighter jets were purchased by the Imperial State of Iran prior to the Islamic Revolution of 1979. 

Meanwhile, semi-official news agencies Fars and Tasnim also reported the sound of blasts without elaborating further. 

Isfahan also is home to sites associated with Iran's nuclear program.

Dubai-based carriers Emirates and FlyDubai began diverting around western Iran at about 04:30 local time (00:30 UTC). The airlines did not explain, but local warnings to aviators suggested that the airspace might have been closed.

Iran later announced it grounded commercial flights in Tehran and across areas of its western and central regions. Online videos purported to show loudspeakers informing customers and travelers of the incident at Imam Khomeini International Airport in Tehran.

Hossein Dalirian, a spokesman for Iran's civilian space program, said on X, formerly Twitter, that several small "quadcopter" drones had been shot down but did not reveal where that happened or if it was part of the ongoing incident in Iran.

Explosions were also heard in Iraq, where a number of Iranian-backed militias are based, with residents of Baghdad reporting they heard sounds of explosions. However, the source of the noise was not immediately apparent.