Iran's Fars news agency says explosions were heard in the central province of Isfahan.
The news agency said on Friday the cause of the sounds is unknown. The explosions were reportedly heard in an area in the province's northwest near the Isfahan airport and an Iranian air force base.
Iran's state-run media also reported explosive sounds in Isfahan, and that air defense systems have been activated in several provinces.
Another Iranian media, Mehr news agency, said that flights have been suspended at several airports in the country.
ABC News and other US media have reported that Israel has launched a missile attack on Iran, citing US government officials.
ABC News, on Thursday night, quoted a senior government official as saying that Israel fired missiles in retaliation to Iran's drone and missile attacks on Israel.
Citing a government official, CNN reported that Israel's attack was not targeted at Iran's nuclear related sites.
Israel had threatened to take retaliatory measures against Iran's large-scale missile and drone attack on Saturday through Sunday. But it is not known yet if there is any connection to the sounds of explosions heard on Friday.