DUBAI/WASHINGTON: Iran's Fars news agency said on Friday that explosions were heard near the airport at the country's central Isfahan city, but the reason was unknown.
"The cause of these sounds is still unknown, and investigations continue until the exact details of the incident are determined," the semi-official Fars news agency said.
A US official said late on Thursday that Israeli missiles have hit a site in Iran, ABC News reported late on Thursday.
Several flights were diverted over Iranian airspace, CNN reported.
Over the weekend, Iran launched hundreds of drones and missiles in a retaliatory strike after a suspected Israeli strike on its embassy compound in Syria.
Most of the drones and missiles were downed before reaching Israeli territory.
Iran told the United Nations Security Council on Thursday that Israel "must be compelled to stop any further military adventurism against our interests" as the UN secretary-general warned that the Middle East was in a "moment of maximum peril."
Israel had said it was going to retaliate against Iran's April 13 missile and drone attack.