As reported by Censor.NET, this was announced by Kommersant newspaper.
"Our sources drew attention to the fact that the mechanism for the bomb detonation, which images had been published by ISIS, was identical to those used by terrorists when blowing up houses at Moscow's Guryanova and Kashyrskoe Shosse streets on Sept. 8 and 13, 1999," the newspaper reports.
They also note that despite the FSB report of the terrorist act, investigative bodies have not yet initiated proceedings against terrorism upon this fact.
Terrorists of Islamic State have published a photo of the bomb. It allegedly was a can from soda water filled with explosive. Besides, the terrorists announced that initially they had had a plan to attack a Western airlines plane, but then targeted the Russian flight.