A fire burns near a military complex at Parchin, Iran after an explosion, June 26, 2020

Iran’s officials are investigating an explosion on or near a military base close to the capital Tehran.

The blast occurred Friday about 12:30 a.m. at Parchin, 30 km (19 miles) southeast of Tehran. The detonation turned the skyline bright orange.

A Defense Ministry spokesman, Brig. Gen. Davoud Abdi, said there was “a gas explosion”. He said there were no casualties and the fire was under control.

Tehran’s head of emergency response told there had been no immediate requests for ambulances or medical aid, but services were on standby.

Abdi said the blast was in a “public area”, indicating it was not on the base. State TV said the detonation was in a natural gas storage facility in a non-residential area.

Western and Israeli officials say that the Parchin base is involved in the Islamic Republic’s nuclear research, and that high explosive components for a nuclear warhead were tested there in the early 21st century.

In 2014, claims circulated that the military site was damaged by a fire or explosion, but the Iranian regime denied access to investigators from the International Atomic Energy Agency.

Iran’s officials deny any connection to a nuclear weapons program.