"The false report about the explosion at Fordow installations is the West's propaganda stunt ahead of the nuclear negotiations to influence the trend and the outcome of talks," Press TV quoted Seyyed Shamseddin Barbroudi, the deputy head of Iran's Atomic Energy Organization, as saying.
Barbroudi rejected the reports, which he labeled "sheer lies."
The British newspaper The Sunday Times quoted unnamed Israeli intelligence officials as confirming an explosion had occurred at the nuclear facility last week. One official said it was still unclear whether the explosion was an accident or caused by sabotage.
The right-wing U.S. news website WND, formerly World Net Daily, first reported the explosion Friday, saying Hamidreza Zakeri, a former member of the Islamic Republic's Ministry of Intelligence and Security, had received reports 240 workers were trapped as a result of an explosion.
Reza Kahlili, an Iranian dissident turned CIA operative, told The Jerusalem Post the incident was "the largest case of sabotage in decades."
The Fordow nuclear facility is 350 feet under a mountain. The WND report said much of the installation was damaged by the explosion, including two elevators said to have been knocked out of commission by the blast, and an emergency exit southwest of the site is unreachable.