Russia’s security services say they have arrested four gunmen responsible for the shooting that killed at least 115 people at a concert hall on the outskirts of Moscow, in one of the worst terror attacks in the country’s history.

The director of Russia’s federal security service (FSB) informed Vladimir Putin that 11 individuals had been arrested in connection with Friday’s terrorist attack at the Crocus City Hall outside Moscow, including four suspects involved in the shooting.

Russian authorities said they had detained 11 people in connection with a terrorist attack on a concert hall in a Moscow suburb, as the death toll from the Friday night assault rose to 115, investigators said.

Among those taken into custody were four people who prosecutors said played a direct role in the violence, in which gunmen shot audience members at close range and set off smoke bombs.

Russia’s Investigative Committee has claimed that the number of deaths following Friday evening’s massacre at the Crocus City concert hall near Moscow has been confirmed at 115 people and warned that this figure is likely to rise.

The service had previously stated that the death toll was 93, but later issued an update announcing that additional bodies were found after emergency services started clearing the rubble.