The death toll has risen to 93 after gunmen stormed a crowded Moscow concert hall on Friday night.
Footage circulating on social media appears to show several men in combat fatigues entering the Crocus City Hall in the west of Moscow, where a popular rock band was playing.
The shooters are believed to have also set fire to the building with explosives.
Russia's National Guard and more than 50 ambulance crews arrived at the scene shortly after the first reports of the attack at around 6pm.
But the blaze raged for more than an hour while firemen were unable to approach the building during the shooting. By 8pm, emergency services had begun to tackle the blaze with the assistance of a helicopter.
At least three children were among the victims, Russian authorities said.
Eleven people have been arrested in connection with the attack.
Crowds had gathered for a concert of Russian rock band Picnic, at the hall which can hold more than 6,000 people. The attack began simultaneously in the auditorium and the foyer, where people were stillqueueing to enter.
“They acted like trained fighters,” a witness told the Mash Telegram channel. 'At the moment of entering the building, the guards and people standing at the door were killed. Then they blocked the main entrance.The terrorists are armed with AKM assault rifles.
“At least two of the attackers are carrying backpacks, possibly with Molotov cocktails.'
Telegram channel Baza carried a report from a security guard at the central entrance to the hall: 'When the shooting began I was standing at the central entrance on the ground floor.
“They started shooting from outside and the windows shattered. Next to the entrance there were three other security guards and they hid behind an advertising board. And those attackers walked past us 10m away.
“They started shooting randomly at people on the ground floor and went towards the concert hall.”
Another witness said: “Everyone started running, there was panic, there was a terrible crush. Everyone was lying down on the ground, crushing each other.”
Chilling footage purportedly filmed within the concert hall, posted on social media last night, appeared to show the heavilyarmed gunmen shooting people at point-blank range as they moved through the hall.
The apparent terror attack comes days after president VladmirPutin was re-elected for another six years.
It also followed a statement earlier this month by the US embassy in Moscow urging Americans to avoid crowded places in the Russian capital in view of an imminent attack, a warning repeated by the UK Foreign Office.
The Islamic State group claimed responsibility for the attack in a statement posted on affiliated social media channels, although neither the Kremlin nor Russian security services have officially assigned blame
In a statement posted by its Aamaq news agency, the Islamic State's affiliate in Afghanistan said it had attacked a large gathering of "Christians" in Krasnogorsk. It was not immediately possible toverify the authenticity of the claim.
