Iranian state media reported a blast in western Tehran early Friday, the latest in a string of mysterious incidents to shake the country in recent weeks.
However, a senior official in that part of the city later denied there had been an explosion.
State broadcaster IRIB said power was cut in several western suburbs near where online reports said an explosion occurred. It gave no further information about the cause of the blast or whether there were casualties.
The governor of Qod city, Leila Vaseghi, told semi-official Fars news agency there had been no explosion but acknowledged a power cut that lasted about five minutes.
It was not immediately clear if the reported incident had taken place in Qod or in a different area of western Tehran, and residents contacted by Reuters in other parts of the city said they had heard no explosion.
There are reportedly several military facilities in the area which could have been the target of sabotage.
A series of fires and blasts have been reported near Iranian military, nuclear and industrial facilities in recent weeks. Iranian officials have said many were caused by industrial accidents.
A bright flash lit up the night sky over Tehran early on June 26, apparently coming from near the near Parchin military site. Fars news agency later said the fire was caused by "an industrial gas tank explosion" near a facility belonging to the defence ministry.
A defence ministry spokesman told state TV that the fire was quickly controlled and there were no casualties.
But after a similar unexplained fire at the Natanz nuclear plant in central Isfahan province on July 2, officials were forced to admit there had been significant damage to the country’s primary uranium enrichment facility.
A spokesman for the Supreme National Security Council of Iran said the “cause of the accident” at the centrifuge assembly plant had been identified, saying more information would be released at a later date “due to security considerations”.
The New York Times reported a Middle Eastern intelligence official and an Islamic Revolutionary Guard Corps commander saying the Natanz incident was caused by an explosive. The head of Israeli intelligence, Yossi Cohen, was later accused of leaking information that Mossad planted a bomb that caused the damage.
On Friday, Iranian foreign ministry spokesman Seyed Abbas Mousavi said Iran would retaliate if it were shown an international sabotage operation had caused the explosion in Natanz.
“It is still too early to make any judgment on the main cause of the blast [in Natanz], and relevant security bodies are probing into every detail of the incident,” Fars reported him as saying.