Facebook has removed 1.5 million videos of the Christchurch mosque shootings “in the first 24 hours” after the attack, the social media giant said on Sunday.

“We continue to work around the clock to remove violating content using a combination of technology and people,” Facebook New Zealand’s Mia Garlick said on Twitter.

Garlick said that, of the removed videos, 1.2 million were “blocked at upload.”

“Out of respect for the people affected by this tragedy and the concerns of local authorities, we’re also removing all edited versions of the video that do not show graphic content,” she said.

Copies of the distressing 17-minute live stream circulated online for hours after the twin attacks that killed 50 people.

Hours after the attack, New Zealand police said they were working to have the footage removed while urging people not to share it.

Later Friday, New Zealand Prime Minister Jacinda Ardern echoed the police’s call, saying that citizens “should not be perpetuating, sharing, giving any oxygen to this act of violence and the message that is sitting behind it.”

The live-stream video shows a white man in camouflage and black clothing driving to what appears to be the Al Noor Mosque on Deans Avenue in Christchurch.

There is nationalist Serbian music playing in the car, and multiple rapid-fire weapons can be seen in the passenger seat. The guns have writing on them, including one featuring the name “Ebba Akerlund,” an 11-year-old girl who was killed in a 2017 terrorist attack in Sweden.

After entering the mosque, the man appears to shoot at least two dozen men in the building as well as at least two people in the street. The video is filmed in the style of a first-person shooter computer game.

He returns to the car to retrieve more weapons and then re-enters the mosque. The video ends with the shooter driving away from the crime scene at full speed and shooting out of the window of his car.

The proliferation of this footage online is dangerous due to the risk of copycat killings, according to Alexander Gillespie, a professor of international law at New Zealand’s University of Waikato.