Radical Muslim militant Shamil Basayev, in a Chechen rebel-linked website, has reportedly claimed responsibility for a extensive blackout that hit large parts of Moscow Wednesday.
But Russian officials repeated Friday their belief that the power outage was caused by a fire and explosion at an energy substation, which they say runs on worn-out equipment.
The militant has claimed responsibility for some of Russia's deadliest terrorist attacks, including last year's elementary school massacre of 330 people.
Yesterday, Russian prosecutors questioned the chief of the country's monopoly power company, Anatoly Chubais, about the blackout.
Russian President Vladimir Putin has accused Unified Energy Systems, the monopoly company that is mostly owned by the government, of negligence.
Wednesday's blackout shut down the Moscow stock market, forced hospitals to switch to emergency power, and left thousands of people stranded in subways.
Some information for this report provided by AP and AFP.