Three of the four suspects charged with carrying out the concert hall attack in Moscow that killed more than 130 people have pleaded guilty in a Russian court.

Moscow’s Basmanny District Court formally charged Dalerdzhon Mirzoyev, 32, Saidakrami Rachabalizoda, 30, Mukhammadsobir Faizov, 19, and Shamsidin Fariduni, 25, with committing a terrorist attack.

The offence carries a maximum sentence of life imprisonment.

The court ordered that the men, all of whom are citizens of Tajikistan, be held in pre-trial custody until May 22.

Mirzoyev, Rachabalizoda and Shamsidin Fariduni all admitted guilt after being charged.

The Herald: Muhammadsobir Fayzov is among the suspectsMuhammadsobir Fayzov is among the suspects (Image: (Alexander Zemlianichenko/AP))

Faizov was brought to court directly from a hospital in a wheelchair and sat with his eyes closed throughout the proceedings. He was attended by medics while in court, where he wore a hospital gown and trousers and was seen with multiple cuts.

The other three suspects appeared in court heavily bruised with swollen faces amid reports in Russian media that they were tortured during interrogation by the security services.

Rachabalizoda had a heavily bandaged ear, and Russian media reported on Saturday that one of the suspects had his ear cut off during interrogation.

The hearing came as Russia observed a national day of mourning following the attack on Friday on the suburban Crocus City Hall concert venue that killed at least 137 people.

The attack, which has been claimed by an affiliate of the so-called Islamic State, was the deadliest on Russian soil in years.

Authorities arrested four suspected attackers on Saturday, with seven more detained on suspicion of involvement in the attack, Russian President Vladimir Putin said in a night-time address to the nation, on Saturday.

He claimed they were captured while fleeing to Ukraine, something that Kyiv firmly denies.

Family and friends of those still missing waited for news of their loved ones as Russia observed a day of national mourning on Sunday.

Events at cultural institutions were cancelled, flags were lowered and TV entertainment and ads were suspended, according to state news agency RIA Novosti.

The Herald:

A steady stream of people took flowers to a makeshift memorial near the Crocus City Hall music venue.

The attack, which has been claimed by an affiliate of the so-called Islamic State, is the deadliest on Russian soil in years.

Mr Putin called the attack “a bloody, barbaric terrorist act” and said Russian authorities captured the four suspects as they were trying to escape to Ukraine through a “window” prepared for them on the Ukrainian side of the border.

Russian media broadcast videos that apparently showed the detention and interrogation of the suspects, including one who told the cameras he was approached by an unidentified assistant to an Islamic preacher via a messaging app and paid to take part in the raid.

Kyiv strongly denied any involvement and the IS group’s Afghanistan affiliate claimed responsibility.

Mr Putin did not mention IS in his speech to the nation and Kyiv accused him and other Russian politicians of falsely linking Ukraine to the assault to stoke fervor for Russia’s fight in Ukraine, which recently entered its third year.

US intelligence officials said they had confirmed the IS affiliate’s claim.

The raid happened just days after Mr Putin cemented his grip on the country for another six years in a vote that followed the harshest crackdown on dissent since the Soviet times.