Explosions heard in Iran's central Isfahan province

TEHRAN, April 19 (Xinhua) -- Three explosions have been heard northeast of Iran's central Isfahan province, the semi-official Fars news agency reported on Friday.

The cause of the explosions has not yet been determined, Fars quoted local sources as saying.

According to Fars, the explosions were heard in Qahjavarestan city, near Isfahan's International Airport and an Iranian army air force base.

Meanwhile, Iran's official IRNA news agency, citing the Iran Airports and Air Navigation Company, reported that all flights in airports in several Iranian cities, including Tehran, Isfahan and Shiraz, were suspended due to security reasons.

IRNA added that Iran activated its air defense system over several cities on Friday.