Blow-by-blow: How the terrifying Moscow ISIS terror attack that killed 143 people unfolded as music fans waited to hear their favourite band

Bullet after bullet tore through hundreds of unsuspecting music fans in Moscow on Friday evening, all of whom had flocked to the western outskirts of the Russian capital to sing their hearts out.

In the ISIS attack, carried out by one of the terror group’s most violent sects, four armed and dangerous men slaughtered innocent civilians who gathered to watch Russian rock band Picnic perform at the Crocus City Hall venue on March 22.

But the concert hadn’t even started when four terrorists, belonging to an ultra-violent sect of the terrorist group, started shooting at innocent civilians.

Details about what exactly happened Friday evening are slowly emerging, and Russian investigators are slowly piecing together the attack.

Here, MailOnline looks at exactly what happened that terrible night.

A clip shows a terrorist running through the security gates of the concert hall

A clip shows a terrorist running through the security gates of the concert hall

Rescuers clear rubble and extinguish fires in the lobby of Crocus City Hall

Rescuers clear rubble and extinguish fires in the lobby of Crocus City Hall

The men were seen in a white, unmarked van shortly before the attack.

Witnesses to the attack, whose words were supported by video footage shared on social media, told the media that the four-man group of automatic Kalashnikovs began firing as they entered the foyer of the venue.

They entered the venue just before 8 p.m. on Friday, walked through the lobby and shot at people waiting in the foyer.

The four terrorists all worked for ISIS-K, an offshoot of ISIS known for its barbarism that was set up in eastern Afghanistan in late 2014 in the wake of US-led airstrikes on ISIS strongholds across Iraq.

The group has been led by Shahab al-Muhajir, an engineer by training and education, since 2020.

His name means ‘Shahab the Migrant’, referring to the fact that he is the first non-Afghan and non-Pakistani person to lead ISIS-K.

More and more gunshots rang through the lobby as the terrorists continued to slaughter innocent people as they walked through the lobby.

The fire consumed a large part of the building

The fire consumed a large part of the building

Crocus Town Hall is located in the urban settlement of Krasnogorsk in the Krasnogorsky District

Police arrived at the scene of the attack, days after the country's presidential elections

Crocus Town Hall is located in the urban settlement of Krasnogorsk in the Krasnogorsky District

Footage shared on social media showed bodies falling one after another as the terrorists made their way to the concert hall.

Inside, concertgoers panicked and headed for the exit. But they were forced to take cover when ISIS gunmen began firing wildly into the gathered crowd.

One terrorist then started a fire that would consume a large part of the building. Witnesses said they saw at least some of them dousing chairs with liquid before setting them on fire.

Russian news reports quoted authorities and witnesses as saying the attackers threw explosives that started the fire, which eventually consumed the building and caused its roof to collapse.

Dave Primov, who survived the attack, told the AP that the gunmen “shot directly into the crowd of people who were in the front rows.”

He described the chaos in the venue as concertgoers rushed to leave the building: “People panicked, started running and collided with each other. Some fell and others trampled them.”

The main hall went up in flames after at least five armed men in camouflage stormed the hall

The main hall went up in flames after at least five armed men in camouflage stormed the hall

Another clip showed at least four armed terrorists firing guns into the crowd

Video footage shows people evacuating the Crocus town hall in the Russian capital

Pictured: Hundreds of people get up from their seats and walk towards the exit as gunshots are heard in the concert hall

After he and others crawled out of the hallway into nearby utility rooms, he said he heard bangs of small explosives and smelled a burning odor as the attackers set the building on fire.

By the time they left the massive building 25 minutes later, it was on fire.

“If it had lasted just a little bit longer, we could have just stayed there burning,” Primov said.

Another who arrived at the scene hours after the attack saw black smoke and flames coming from the roof of the concert hall, which can accommodate up to 6,000 people. Helicopters tried to extinguish the flames that engulfed the large building.

Eventually, emergency services were able to enter and treat the injured and authorities were able to begin their investigation into what exactly had happened.

Investigators said some died of gunshot wounds and others in a massive fire that broke out in the complex. Reports say the gunmen started the fire with gasoline from jerry cans they carried in their backpacks.

The hall, which is still ablaze, has a capacity of 6,000 spectators

The hall, which is still ablaze, has a capacity of 6,000 spectators

Seventy ambulances attended the scene of the building that went up in flames

Seventy ambulances attended the scene of the building that went up in flames

1711246171 354 Blow by blow How the terrifying Moscow ISIS terror attack that killed

Gunmen have attacked a concert hall during a mass shooting in Moscow

People fled in panic. Baza, a news source with good contacts in Russia’s security and law enforcement agencies, said 28 bodies were found in a toilet and 14 on a staircase. “Many mothers were found hugging their children,” it said.

Investigators searched through the charred rubble of the venue on Saturday for more victims, and authorities said the death toll could still rise.

U.S. intelligence officials believe members of Islamic State in Khorasan Province, or ISIS-K, carried out the attack. Tonight, the US officially refuted Vladimir Putin’s claims that the attacks were ordered by Ukraine.

“ISIS bears sole responsibility for this attack. There was no involvement whatsoever from Ukraine,” National Security Council spokeswoman Adrienne Watson said in a statement.

ISIS-K, founded in late 2014 in eastern Afghanistan in the wake of US-led airstrikes on ISIS strongholds across Iraq, is known for its extreme brutality.