DUBAI: A loud blast was heard at a military plant in Iran’s central city of Isfahan, but a security official said there were no casualties, Iranian state broadcaster IRIB said on its website early on Sunday.

“The explosion took place in one of the munitions manufacturing centres of the Defence Ministry and, according to an announcement by the …deputy Isfahan governor for security, there were no casualties,” IRIB reported.

The official, Mohammad Reza Jannesar, later told state television: “The damages are being investigated as well as the causes and elements that caused this explosion and .. will be announced later.”

There have been a number of explosions and fires around Iranian military, nuclear and industrial facilities in the past few years.

The blasts have at times caused concern amid tensions over Iran’s nuclear programme with Israel and the United States.

Israel has long threatened military action against Iran if indirect talks between Washington and Tehran fail to salvage a 2015 nuclear pact.