What just happened? YouTube star Felix 'Pewdiepie' Kjellberg says he is "absolutely sickened" to learn that one of the perpetrators in the attacks on two New Zealand mosques mentioned his name during a livestream of the shooting.

Forty-nine people were killed and at least 20 wounded in the tragedy, which took place in Christchurch, New Zealand. One gunman, who is thought to be Australian, livestreamed the shooting on Facebook using what is believed to be a head-mounted camera. In the first few minutes of the clip, he says, "Remember, lads: subscribe to Pewdiepie."

Facebook said it had removed the shooter's Facebook and Instagram accounts and deleted the video. Police are asking people not to share the "extremely distressing" footage online. Before the attack began, he posted a message on 8Chan, part of which read: "Please do your part by spreading my message, making memes and shitposting as you usually do."

Pewdiepie released a statement regarding the incident on Twitter earlier this morning. "Just heard news of the devastating reports from New Zealand Christchurch," he wrote. "I feel absolutely sickened having my name uttered by this person. My heart and thoughts go out to the victims, families and everyone affected by this tragedy."

The BBC reports that a man in his late twenties was charged with murder and will appear in court on Saturday morning. Two other men and one woman were detained nearby and firearms seized, Police Commissioner Mike Bush said.

The internet has been awash with people posting the "subscribe to Pewdiepie" message in recent months, as he competes to become the most-subscribed channel once again. He currently has 89.3 million subs, putting him just behind T-series, India's largest Music Label and Movie Studio, which has 89.4 million subscribers.

In December, 50,000 printers were hijacked to promote Pewdiepie's channel, while January saw hackers do the same thing with Chromecast devices.