Gunmen in combat gear have killed at least 40 people after bursting into a concert hall in Moscow, spraying bullets into the crowd and throwing explosives.

Footage showed at least four people in military-style fatigues walking up to a crowd at the entrance of the Crocus City concert hall in north-west Moscow and shooting them at point-blank range with automatic weapons.

The gunmen also blew up part of the concert hall, prompting a fire that had caused the roof of the building to partially collapse by Friday evening.

At least 100 people were evacuated but an unknown number were trapped inside late on Friday night, according to reports, while more than 130 people were injured.

At least five gunmen barricaded themselves inside the venue, according to Basa, a Telegram channel linked to the Russian security services.

Moscow’s foreign ministry called the incident “a bloody terrorist attack”.

“The entire world community must condemn this despicable crime,” Russian spokesman Maria Zakharova wrote on the Telegram messaging app.

Heavily armed Russian special forces surrounded the venue, with helicopters flying overhead, as Moscow triggered its anti-terrorist operation plan.

Officials have not named any suspects behind the attack but Ukraine denied any involvement.

“Let’s be clear, Ukraine absolutely has nothing to do with these events,” Mykhailo Podolyak, Ukraine’s presidential aide, said on Telegram.

The White House also said Kyiv was not behind the attack. “There is no indication at this time that Ukraine or Ukrainians were involved in the shooting,” John Kirby, National Security Council spokesman, told reporters. 

Moscow retorted that it was too early to rule out a Ukrainian link to the attack. “On what basis do officials in Washington draw any conclusions about anyone’s innocence in the midst of a tragedy?” the foreign ministry asked.

‘They must be destroyed’

Dmitry Medvedev, the former Russian president, said that if Ukraine was found to be behind the attack, Russia would hunt the perpetrators down and kill them.

“If it is established that these are terrorists of the Kyiv regime, all of them must be found and ruthlessly destroyed as terrorists,” Mr Medvedev wrote on Telegram. “Official representatives of the state that committed such a crime” would also be punished, he added.

The attack, the deadliest in Russia for years, comes less than a week after Vladimir Putin won a presidential election, extending his 24-year presidency to at least 2030. He has outlawed anti-Kremlin protests, especially over his war in Ukraine.

Footage from the attack showed people shot dead lying slumped across blood-soaked benches and crumpled by the glass doors of the venue.

Another video showed people who had been waiting for a concert by the Soviet-era rock band Picnic to begin. In the video, word spreads of an attack and people start leaving. Less than a minute later, there are shots in a corner of the concert hall, and people start screaming and ducking for cover. 

‘We just ran’

One witness described his escape to Russian media. “Someone broke a window into the parking lot and we just ran out without our things, without anything, only with what we were wearing,” he said.

A state media journalist at the hall said they saw people crawling to safety. “People who were in the hall were led on the ground to protect themselves from the shooting for 15 or 20 minutes,” the journalist was quoted as saying.

Other people described locking themselves in the basement, smashing down fire doors with axes and running across broken glass to escape.

At least 6,200 people had bought tickets to the concert and Moscow region emergency officials said that police, firemen and special forces were trying to evacuate hundreds of people.

The US embassy in Moscow had issued warnings for the past fortnight that a terror attack was planned in Moscow and had told US citizens to stay away from large crowds, specifically mentioning concerts.

Commentators said that security at the concert appeared to have been unusually light.

Apartment attacks in 1999

Putin has previously been accused of using terror attacks in Russia to tighten his rule. Chechen terrorists were blamed for bomb attacks on apartment blocks in Russia in 1999 that killed 300 people shortly before Putin took over as president, promising to improve security.

In 2002, Chechen terrorists captured the Nord-Ost theatre in Moscow and in 2003 Chechen rebels captured a school in Beslan in North Ossetia, southern Russia. Several hundred people were killed in both attacks, forcing Putin to promise to improve security.

Since the promotion of the Kremlin-backed Ramzan Kadyrov in 2007 as Chechnya’s leader, though, most Chechen rebels have laid down their arms.