Chemistry students with ultranationalist views may be behind a string of recent bombings targeting Federal Security Service buildings in Moscow, a law enforcement official told Interfax on Friday.
The choice of targets, the lack of any victims, and the way the bombs were made suggest that students are the prime suspects, not professional terrorists, the unidentified official said. He added that the bomb makers were not likely to be members of organized ultranationalist groups.
The first blast took place Wednesday near the FSB Academy on Michurinsky Prospekt in southern Moscow. No one was injured.
On Friday, two explosions took place outside an apartment building near Ulitsa Milashenkova in northeastern Moscow that was reportedly built by the FSB's construction service. No injuries were reported.
Chechen rebel leader Doku Umarov claimed responsibility for the first blast, but Interfax reported Saturday that investigators doubt the claim.
Security has been boosted at all FSB colleges, apartment buildings and offices in Moscow, Interfax said.