The four men suspected of carrying out a bloody attack on a concert hall near Moscow, killing at least 137 people, were arraigned in a district court late Sunday and charged with committing a terrorist act.

The four, who were from Tajikistan but worked as migrant laborers in Russia, were remanded in custody until May 22, according to state and independent media outlets reporting from the proceedings, at Basmanny District Court. They face a maximum sentence of life in prison.

The press service of the court only announced that the first two defendants, Dalerjon B. Mirzoyev and Saidakrami M. Rachalbalizoda, pleaded guilty to the charges. It did not specify any plea from the other two, Mediazona, an independent news outlet, reported.

The men looked severely battered and injured as each of them was brought into the courtroom separately. Videos of them being tortured and beaten while under interrogation circulated widely on Russian social media.

Muhammadsobir Z. Fayzov, a 19-year-old barber and the youngest of the men charged, was rolled into the courtroom from a hospital emergency room on a tall, orange wheelchair, attended by a doctor, the reports said. He sat propped up in the wheelchair inside the glass cage for defendants, wearing a catheter and an open hospital gown with his chest partially exposed. Often speaking in Tajik through a translator, he answered questions about his biography quietly and stammered, according to Mediazona.

Mr. Rachabalizoda, 30, had a large bandage hanging off the right side of his head where interrogators had sliced off a part of his ear and forced it into his mouth, the reports said, with the cutting captured in a video that spread online.