An explosion was heard north-west of the Iranian city of Isfahan early Friday morning, according to the country’s semi-official Fars news agency.
Fars said that it occurred near the city’s international airport. But it offered no explanation on the possible cause.
Isfahan province is home to a large air base, a major missile production complex and several nuclear sites.
The incident comes as tensions remain high across the Middle East after Iran’s unprecedented missile-and-drone attack on Israel on Saturday.