Four men accused of attacking concert outside Moscow have been charged with terrorism.
The appeared in a court showing signs of severe beating.
The charges came as Russia lowered flags to half-mast for a day of mourning over the deadliest attack claimed by ISIL (ISIS).
At least 137 people – three children among them – were killed and 182 injured in the attack. Sources said that condition of about 40 injured is critical.
Basmanny District Court of Moscow identified the four accused as Dalerdzhon Mirzoyev, 32; Saidakrami Rachabalizoda, 30; Shamsidin Fariduni, 25; and Mukhammadsobir Faizov, 19.
All the suspects are citizens of Tajikistan. They were charged with committing a group terrorist attack resulting in the death of others. The crime carries a maximum sentence of life imprisonment.
The court ordered to hold the suspects in pre-trial custody until May 22.
Source said that Mirzoyev and Rachabalizoda admitted guilt for the attack.
The accused were tortured during interrogation by the security forces.
At court, Mirzoyev, Fariduni and Rachabalizoda showed signs of heavy bruising with swollen faces. Faizov was brought to court from a hospital sitting in a wheelchair with his eyes closed. Wearing hospital gown, Faizov was attended by medics while in court. Rachabalizoda also had a heavily bandaged ear.
