All the four accused in the concert hall attack in Moscow have been remanded in custody as Russia observed a national day of mourning following the attack claimed by the Islamic State.
As per a report by news agency AFP, all four suspects have been charged with terrorism and face life imprisonment, according to Moscow's Basmanny district court.
Their detention is set until May 22 but could be extended depending on the date of their trial.
According to the AFP report, the court said that the two of the defendants had pleaded guilty while one of them, from Tajikistan, had "entirely acknowledged his guilt".
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The attacks that took place on Friday after gunmen opened fire in Crocus City Hall in Moscow's northern suburb of Krasnogorsk have killed 137 people so far.
Russian President Vladimir Putin has vowed to punish those responsible for the "barbaric terrorist attack". On Saturday, Putin said that the four gunmen had been arrested while trying to flee to Ukraine while Kyiv has denied any connections with the attack.
The Russian President made no reference to the Islamic State group's claims of responsibility.
Meanwhile, the IS posted on Telegram on Saturday that the attack was "carried out by four IS fighters armed with machine guns, a pistol, knives, and firebombs" as part of "the raging war" with "countries fighting Islam".
External Affairs Minister S Jaishankar extended his "deepest condolences” to his Russian counterpart Sergey Lavrov during a conversation on Sunday.
“Spoke to Russian Foreign Minister Sergey Lavrov. Conveyed our deepest condolences on the loss of lives in the horrific terrorist attack in Moscow," Jaishankar said in a post on X.
The Russian Embassy in India opened an online book of condolence on Sunday for people who wish to offer condolence to the families of the terror attack victims.