Four men accused of staging the Russia concert hall attack that killed more than 130 people appeared before a Moscow court today showing signs of severe beatings as they faced formal terrorism charges. One appeared to be barely conscious during the hearing.

A court statement said two of the suspects accepted their guilt in the assault after being charged in the preliminary hearing, though the men’s condition raised questions about whether they were speaking freely. There had been earlier conflicting reports in Russian media outlets that said three or all four men admitted culpability.

Moscow’s Basmanny District Court formally charged Dalerdzhon Mirzoyev, 32; Saidakrami Rachabalizoda, 30; Shamsidin Fariduni, 25; and Mukhammadsobir Faizov, 19, with committing a group terrorist attack resulting in the death of others. The offence carries a maximum sentence of life imprisonment.

Mukhammadsobir Faizov, a suspect in the Crocus City Hall shooting, appears in a Moscow court. Photo / AP

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

Russian media had reported that the men were tortured during interrogation by the security services and Mirzoyev, Rachabalizoda and Fariduni showed signs of heavy bruising, including swollen faces.

Rachabalizoda also had a heavily bandaged ear. Russian media yesterday said one of the suspects had his ear cut off during interrogation. The Associated Press couldn’t verify the report or the videos purporting to show this.

Shamsidin Fariduni, a suspect in Saturday's Crocus City Hall shooting, in a glass cage during a court appearance. Photo / AP

The fourth suspect, Faizov, was brought to court 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.

Court officials said Mirzoyev and Rachabalizoda admitted guilt for the attack after being charged.

The hearing came as Russia observed a national day of mourning for Saturday’s attack 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 Islamic State (Isis) group, is the deadliest on Russian soil in years.

Saidakrami Murodali Rachabalizoda, a suspect in the Crocus City Hall shooting on Saturday, sits in a glass cage. Photo / AP

Russian authorities arrested the four suspected attackers yesterday, with seven more people detained on suspicion of involvement in the attack, Russian President Vladimir Putin said in an address to the nation yesterday. He claimed they were captured while fleeing to Ukraine, something Kyiv firmly denied.

Events at cultural institutions were cancelled yesterday, flags were lowered to half-mast and television entertainment and advertising were suspended, according to state news agency RIA Novosti. A steady stream of people added to a makeshift memorial near the burned-out concert hall, creating a huge mound of flowers.

“People came to a concert, some people came to relax with their families, and any one of us could have been in that situation. And I want to express my condolences to all the families that were affected here and I want to pay tribute to these people,” Andrey Kondakov, one of the mourners who came to lay flowers at the memorial, told AP.

Dalerdzhon Mirzoyev, one of the suspects in the Crocus City Hall shooting. Photo / AP

“It is a tragedy that has affected our entire country,” kindergarten employee Marina Korshunova said. “It just doesn’t even make sense that small children were affected by this event.” Three children were among the dead.

Rescuers continued to search the damaged building and the death toll rose as more bodies were found as family and friends of some of those still missing waiting for news. Moscow’s Department of Health yesterday said it had begun identifying the bodies of those killed via DNA testing and the process would take at least two weeks.

Igor Pogadaev was desperately seeking any details about his wife, Yana Pogadaeva, who went to the attack concert. The last he heard from her was when she sent him two photos from the Crocus City Hall music venue.

After Pogadaev saw the reports of gunmen opening fire on concertgoers, he rushed to the site but couldn’t find her in the numerous ambulances or among the hundreds of people who had made their way out of the venue.

“I went around, searched, I asked everyone, I showed photographs. No one saw anything, no one could say anything,” Pogadaev told AP in a video message.

He watched flames bursting out of the building as he made frantic calls to a hotline for relatives of the victims, but received no information.

People in St Petersburg place flowers at a spontaneous memorial in memory of the victims of the Moscow attack. Photo / AP

As the death toll mounted, Pogodaev scoured hospitals in the Russian capital and the Moscow region, looking for information on newly admitted patients.

His wife wasn’t among the 182 reported injured nor on the list of 60 victims authorities had already identified, he said.

The Moscow Region’s Emergency Situations Ministry posted a video yesterday showing equipment being used to dismantle the damaged music venue to give rescuers access.

Putin has 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 President Vladimir Putin lights a candle to commemorate the victims of an attack on the Crocus City Hall concert venue. Photo / AP

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.

Putin didn’t mention Isis in his speech to the nation, and Kyiv accused him and other Russian politicians of falsely linking Ukraine to the assault to stoke fervour for Russia’s fight in Ukraine, which recently entered its third year.

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

“Isis bears sole responsibility for this attack. There was no Ukrainian involvement whatsoever,” National Security Council spokeswoman Adrienne Watson said.

The US shared information with Russia in early March about a planned terrorist attack in Moscow and issued a public warning to Americans in Russia, Watson said.

A woman in Simferopol, Crimea, places flowers in memory of the victims of the attack in Moscow. Photo / AP

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

Some commentators on Russian social media questioned how authorities, who have relentlessly suppressed any opposition activities and muzzled independent media, failed to prevent the attack despite the US warnings.

Isis, which fought against Russia during its intervention in the Syrian civil war, has long targeted Russia. In a statement posted by the group’s Aamaq news agency, the Isis Afghanistan affiliate said it had attacked a large gathering of “Christians” in Krasnogorsk.

A suspect in the Crocus City Hall shooting is escorted to the Russian Investigative Committee headquarters. Photo / AP

The group issued a new statement on Sunday on Aamaq, saying the attack was carried out by four men who used automatic rifles, a pistol, knives and firebombs. It said the assailants fired at the crowd and used knives to kill some concertgoers, casting the raid as part of Isis’ ongoing war with countries it says are fighting against Islam.

In October 2015, a bomb planted by Isis downed a Russian passenger plane over Sinai, killing all 224 people on board, most of them Russian vacationers returning from Egypt.

The group, which operates mainly in Syria and Iraq but also in Afghanistan and Africa, also has claimed responsibility for several attacks in Russia’s volatile Caucasus and other regions in past years. It recruited fighters from Russia and other parts of the former Soviet Union.