Hawzah News Agency (Christchurch, New Zealand) – Facebook has acted quickly to remove footage appearing to show a shooting at a mosque in New Zealand.

Four people are in custody after 49 people died in coordinated attacks on two mosques in Christchurch, according to New Zealand Police Commissioner Mike Bush. The unverified footage was reportedly livestreamed on Facebook by an alleged attacker.

"Police are aware there is extremely distressing footage relating to the incident in Christchurch circulating online," New Zealand police said in a statement on Twitter. "We would strongly urge that the link not be shared. We are working to have any footage removed."

Authorities reported 49 dead and another 20 wounded in the shootings, which happened Friday afternoon local time. One suspect has been charged with murder.

Facebook told CNET it had removed the unverified footage and was also pulling down "praise or support" posts for the shootings.

"New Zealand Police alerted us to a video on Facebook shortly after the livestream commenced and we removed both the shooter's Facebook account and the video," said Mia Garlick, a Facebook representative in New Zealand. "We're also removing any praise or support for the crime and the shooter or shooters as soon as we're aware. We will continue working directly with New Zealand Police as their response and investigation continues.

"Our hearts go out to the victims, their families and the community affected by this horrendous act."

In a tweet from its official account, YouTube also committed to removing footage.

"Our hearts are broken over today's terrible tragedy in New Zealand," read the statement. "Please know we are working vigilantly to remove any violent footage."

New Zealand Prime Minister Jacinda Ardern said at a news conference that the shootings are "one of New Zealand's darkest days."

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