At least 40 people have been killed after gunmen burst into a concert hall in Moscow and fired at the crowd, according to Russia’s Federal Security Service.
The gunmen, wearing combat fatigues, also caused a huge blaze at the Crocus City Hall. Russian media reported the venue’s roof was collapsing.
The attack, which Russian authorities are investigating as terrorism, is Russia’s deadliest in recent years.
More than 100 were wounded, the FSB said.
Footage taken inside the auditorium shows up to four gunmen firing automatic weapons as people crouch and hide behind seats.
Follow latest Russia shooting updates
In other videos posted by Russian media and Telegram channels, extended rounds of gunfire could be heard while two men with rifles were moving through the venue’s mall.
Russian news reports said the attackers threw explosives, triggering the massive blaze at the venue, where flames and plumes of black smoke could be seen rising into the air.
There were no immediate claims of responsibility for the raid.
Moscow Mayor Sergei Sobyanin described the attack as a “huge tragedy” and cancelled all mass gatherings scheduled for the weekend.
Russian authorities said security had been tightened at Moscow’s airports and railway stations.
President Vladimir Putin was receiving regular updates about the shooting, Kremlin spokesman Dmitry Peskov said.
White House national security adviser John Kirby said he could not yet speak about all the details but that “the images are just horrible. And just hard to watch”.
Mr Kirby said there was “no indication at this time that Ukraine, Ukrainians were involved”.
But Russia said if the US knew for sure Ukraine was not involved then it should share any information it had.
Russian Foreign Ministry spokeswoman Maria Zakharova said: “On what basis do officials in Washington draw any conclusions in the midst of a tragedy about someone’s innocence?”
She said if Washington had information it should be shared and if it had no information it should not be talking in such a way.
It comes days after Mr Putin secured his fifth term as Russia’s president in an electoral landslide.
This breaking news story is being updated and more details will be published shortly.
Please refresh the page for the fullest version.
You can receive Breaking News alerts on a smartphone or tablet via the Sky News App. You can also follow @SkyNews on X or subscribe to our YouTube channel to keep up with the latest news.