Armed men burst into the Crocus City Hall near Moscow on Friday, killing at least 93 people and injuring many dozens more in the deadliest attack in Russia since the 2004 Beslan school siege.
What do we know about the attack?
THE ATTACK
The men, armed with Kalashnikov automatic weapons, arrived at the Crocus City Hall at around 7:40 p.m. (1640 GMT) in a minivan. Russian media said there were up to five men.
Federal Security Service (FSB) Director Alexander Bortnikov informed President Vladimir Putin that there were four attackers, the Kremlin said.
They began shooting civilians at point-blank range. They shot people through the glass doors near the entrance turnstiles to the venue, witnesses said, then moved on towards the concert hall itself.
Videos showed the men shooting screaming civilians with automatic weapons. Bodies were then seen motionless.
As people took their seats for a concert by Soviet-era rock group "Picnic", shooting could be heard inside the 6,200-seat hall where all the tickets had been sold out. The group had been planning to perform their new hit "Afraid of Nothing."
The attackers were shown on videos from the scene methodically shooting at concertgoers as people rushed for the exits.
The men then set fire to the concert hall, pouring a liquid on the curtains and chairs before igniting it.
Reuters video showed flames leaping above the hall and plumes of black smoke billowing into the sky as the blue lights of hundreds of emergency vehicles flashed across the night.
The fire, which spread across nearly 13,000 square meters took hours to contain. The roof collapsed.
DEATH TOLL
Russia's investigative committee said on Saturday the death toll was 93.
Some sources said 145 people were injured. The Moscow Region said 121 people had been wounded. Earlier it had said 60 of the injured were in a critical condition.
RESPONSIBILITY
ISIS, the militant group that once sought control over swathes of Iraq and Syria, claimed responsibility for the attack, the group's Amaq agency said on Telegram.
"ISIS fighters attacked a large gathering of Christians in the city of Krasnogorsk on the outskirts of the Russian capital, Moscow, killing and wounding hundreds and causing great destruction to the place before they withdrew to their bases safely," the statement said.
The United States has intelligence confirming ISIS’s claim of responsibility for a deadly shooting at a concert near Moscow, two US officials said on Friday.
The officials said the United States had warned Russia in recent weeks about the possibility of an attack - a move they said prompted the US embassy in Moscow to issue a warning to Americans.
Two weeks ago the US embassy in Russia warned that "extremists" had imminent plans for an attack in Moscow.
Hours before the embassy warning, the Federal Security Service (FSB) said it had foiled an attack on a Moscow synagogue by ISIS’s affiliate in Afghanistan, which is known as ISIS-Khorasan or ISIS-K and seeks a caliphate across Afghanistan, Pakistan, Turkmenistan, Tajikistan, Uzbekistan and Iran.
"We did warn the Russians appropriately," one of the US officials said, speaking on condition of anonymity.
THE ATTACKERS
Russian media said there were five men. Reuters was unable to confirm just how many there were.
Russian investigators showed pictures from inside the hall showing an automatic weapon, vests with multiple spare magazines and bags of spent bullet casings that had been collected from the scene.
A grainy picture was published by some Russian media of two of the alleged attackers in a white car.
The FSB said 11 people had been detained, including all four of the attackers.
Russian lawmaker Alexander Khinshtein, a former journalist, said that the white Renault used by the suspects was found in a village in the Bryansk region, about 340 km (210 miles) southwest of Moscow.
"One terrorist was detained on the spot, the rest fled into the forest," Khinshtein said.
He said a pistol, a Kalashnikov magazine and passports of Tajik citizens were found in the car. Reuters was unable to verify that information.
