A US official told ABC News on Thursday night that Israel launched an attack on Iran and that that Israeli missiles had hit a site in Iran.

A military source told Fox News that Israel carried out a "limited" strike in Iran.

The comments came after Iran's Fars news agency reported explosions near the Isfahan airport and an Iranian military air base.

“The cause of these sounds is still unknown, and investigations continue until the exact details of the incident are determined,” it said.

Meanwhile, reports emerged of civilian flights being diverted from Iran and explosions in the country. The Iranian airports authority announced the suspension of flights at the airports in Tehran, Isfahan and Shiraz.

An official Iranian spokesman said the country’s air defense had successfully shot down "a number of small aircraft". Iranian media reported that the country’s nuclear facilities were not harmed by the strikes.

Iranian television reported that three unmanned aerial vehicles were spotted over Isfahan at 3:30 a.m. local time. The report said that they were destroyed in the air.

Three Iranian sources confirmed to the New York Times that the air base in Isfahan was hit in the attack.

The Iranian news agency Tasnim claimed that contrary to reports, there was no foreign attack in Isfahan or any other part of the country. The report said that the air defenses fired interceptor missiles in some places, but this is due to the high sensitivity of the air defense systems.

The Iranian Revolutionary Guards announced a high alert at all their bases in Iran.

A senior US official told Reuters that the United States did not take part in the Israeli attack and that Jerusalem informed Washington about the attack ahead of time.

Meanwhile, a Syrian security source said that an Israeli attack took place in southern Syria and targeted a radar base.

At the same time, there were reports of increased activity of US aircraft over Iraq.

Bloomberg reported that Israel informed the US earlier in the day that the response to the Iranian attack would occur within 24-48 hours.

Israeli officials have not commented on the reports thus far.