Four men charged with committing an act of terrorism in a Moscow concert hall attack, which killed at least 137 people, remain in custody.
All four suspects face life imprisonment. The attack on 22 March was claimed by the Islamic State (IS).
The men’s detention is set until 22 May but may be extended depending on the date of their trial.
The court said two of the defendants had pleaded guilty, and one of them, from Tajikistan, had “entirely acknowledged his guilt”.
President Vladimir Putin has vowed to punish those behind the “barbaric terrorist attack”, and said the four gunmen had been arrested while trying to flee to Ukraine. Kyiv has strongly denied any connection to the attack.
Mr Putin has made no public reference to the IS group’s claims of responsibility.
At least 137 people, including three children, were killed last Friday evening when gunmen stormed the Crocus City Hall in Moscow’s northern suburb of Krasnogorsk then set fire to the building.
It is the deadliest attack in Europe to have been claimed by IS.
Russia’s Investigative Committee posted a video of the four suspects being dragged into its headquarters in Moscow.
There was no statement on the other seven suspects arrested in connection with the attack.
Officials have said the gunmen were all foreign nationals.
‘Machine guns, knives, firebombs’
The Islamic State group posted Saturday on Telegram 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”.
A video, apparently filmed by the gunmen, has been posted on social media accounts typically used by IS, according to the SITE intelligence group.
The video – which appears to have been filmed from the lobby of the concert venue – shows several individuals with blurred faces and garbled voices, firing assault rifles with inert bodies strewn on the floor and a fire starting in the background.
Russian investigators said that after walking through the theatre shooting spectators, the gunmen set fire to the building, trapping many inside.
Health officials said the number of casualties had risen to 182, with 101 people still in hospital, of whom 40 were in “critical” or “extremely critical” condition.
The attack was the deadliest in Russia since the Beslan school siege in 2004.
