At least 40 people were killed and 145 wounded on Friday when camouflage-clad gunmen fired with automatic weapons on concertgoers near Moscow in one of the deadliest attacks on Russia in decades.
Islamic State, the militant group that once sought control over swathes of Iraq and Syria, claimed responsibility for the attack, the group's Telegram channel said.
At least five gunmen began shooting civilians cowering in the Crocus City Hall just before Soviet-era rock group "Picnic" was about to perform to a full house at the 6,200-seat theatre in a suburb west of Moscow.
Verified video showed people taking their seats in the hall then rushing for the exits as repeated gunfire echoed above screams. Other video showed men shooting at groups of people. Some victims lay motionless in pools of blood.
"Suddenly there were bangs behind us - shots. A burst of firing - I do not know what," one witness, who asked not to be identified by name, told Reuters.
"A stampede began. Everyone ran to the escalator," the witness said. "Everyone was screaming; everyone was running."
Russia's Federal Security Service(FSB), the main successor to the Soviet-era KGB, said about 40 people were killed while a regional ministry, quoted by the Tass news agency, said 145 were wounded. The FSB said extra security measures were imposed.
The death toll made it one of the worst attacks on Russia since the 2004 Beslan school siege, when Islamist militants took more than 1,000 people, including hundreds of children, hostage.
Children were reported to be among the dead and injured at the concert. Dozens of ambulances arrived at the Sklifosovsky emergency care institute in Moscow.
At Crocus City Hall, flames leapt into the sky, and plumes of black smoke rose above the venue as hundreds of blue lights from emergency vehicles flashed in the night, Reuters pictures and video showed.
Helicopters sought to douse flames that engulfed the large building, and evacuated around 100 people from the basement. The roof of the venue was collapsing, state news agency RIA said.
Russian media reported a second blast at the venue. Some outlets said gunmen barricaded themselves in the building. RIA said the gunmen were presumed to be at large.
In a post on Telegram, Islamic State said its fighters attacked on the outskirts of Moscow "killing and wounding hundreds and causing great destruction to the place before they withdrew to their bases safely."
Russian Foreign Ministry Spokeswoman Maria Zakharova said it was a "bloody terrorist attack" that the entire world should condemn.
The United States, European and Arab powers and many former Soviet republics expressed shock, condemned the attack and sent their condolences. Ukrainian presidential adviser Mykhailo Podolyak denied any Ukrainian involvement.
ATTACK WARNING
Two weeks ago, the U.S. embassy in Russia warned that "extremists" had imminent plans for an attack in Moscow.
The embassy issued its warning several hours after the FSB said it had foiled an attack on a Moscow synagogue by a cell of Islamic State.
"While events continue to unfold, we strongly recommend that U.S. citizens in Moscow avoid the area, follow the instructions of local security services and keep an eye on local media updates," the U.S. embassy said on Friday.
Putin was informed in the first minutes of the attack and is regularly being updated, the Kremlin said.
"The president constantly receives information about what is happening and about the measures being taken through all relevant services. The head of state gave all the necessary instructions," Kremlin spokesperson Dmitry Peskov said.
SECURITY TIGHTENED
After the attack, Russia tightened security at airports, transport hubs and across the capital - a vast urban area of over 21 million people. All large-scale public events were cancelled across the country.
"A terrible tragedy occurred in the shopping centre Crocus City today," Moscow Mayor Sergei Sobyanin said. "I am sorry for the loved ones of the victims."
The White House said that images of the shooting were hard to watch, while Germany's foreign ministry called the images "horrific."
"...Our thoughts obviously are going to be with the victims of this terrible, terrible shooting attack," White House spokesman John Kirby said.
Kirby said there was "no indication at this time that Ukraine, or Ukrainians were involved in the shooting."
Russia's Zakharova questioned how the U.S. knew this and said Washington should immediately pass any information it had to Moscow, or stop making such statements.
