Worshippers, possibly dead or wounded, lay huddled on the floor of the mosque, the video showed.
While officials are yet to confirm exactly what happened or verify the footage, PewDiePie - whose real name is Felix Arvid Ulf Kjellberg - has issued a statement via Twitter condemning the attack.
Tarrant was arrested in a auto, which police said was carrying improvised explosive devices, 36 minutes after they were first called.
It is clear that this can now only be described as a terrorist attack.
Two other people were in custody and police said they were working to understand their involvement. Police say that this person was a member of the public armed with a gun with the intention of assisting officers.
Two of the guns were semi-automatic weapons and two were shotguns, she said, before telling media members that the attack would have an impact on gun laws in the country.
Police and military personnel walk at the carpark compound of the district court after Friday's mosque attacks, in Christchurch, New Zealand, March 16, 2019. As a result of the attack, she has upgraded the country's terror threat level from low to high.
New Zealand media reported that between nine and 27 people were killed, but the death toll could not be confirmed.
Police stand guard at Christchurch Hospital.
Funerals were planned on Saturday for some of the victims, several who were born overseas.
Deakin University counter-terrorism expert Greg Barton identified one of the weapons as a AR-15, the same assault rifle used in the 2017 Las Vegas mass shooting that killed 58 people.
She pronounced it "one of New Zealand'sdarkest days". Indonesian Muslim leaders expressed anger at the shooting rampage while urging Muslims to show restraint.
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A cricket match between New Zealand and Bangladesh scheduled to start Saturday was canceled after the Bangladesh cricket team had a narrow escape.
Ardern, who flew to Christchurch on Saturday, said she had spoken to Trump, who had asked how he could help.
Ontario Premier Doug Ford strongly condemned the horrifying attack, tweeting, "I join people across Ontario and Canada and stand with all legislators at Queen's Park in condemning this hatred and violence against our Muslim brothers and sisters".
Political across Asia and the Middle East voiced concern over the targeting of Muslims.
New Zealand Prime Minister Jacinda Ardern rounded on purveyors of hate during a news conference Friday.
The document railed against immigrants and immigration, saying, "as long as a white man still lives, they will NEVER conquer our lands and they will never replace our people".
"He had a big gun".
Witness Len Peneha said he saw a man dressed in black enter the mosque and then heard dozens of shots, followed by people running from the mosque in terror. Facebook said later that it had removed both the shooter's Facebook and Instagram accounts, and taken down the video after the shooting and all posts supporting the attack.
According to the Independent, the suspects are alleged to have called people attending Friday prayers at a near-by mosque "terrorists'".
Among the wounded, two were in a critical condition, including a four-year-old child. At one stage the shooter returns to his auto, changes weapons, re-enters the mosque and again begins shooting.
"It brings actually a feeling of fear that we hope we can actually overcome and try to avoid by spreading more awareness, by educating our community and the larger community that these things shouldn't be an obstacle in front of us to enjoy the freedom of religion", said Wahb.
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She said: "Obviously we continue to be working to leave in an orderly fashion with a deal, but we have made funding available". To take no deal off the table, it is not enough to vote against no deal - you have to agree to a deal.
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Other players rumored to be destined for Arsenal include; Sokratis Papastathopoulos, from Borussia Dortmund, and Saul Niguez. If they are rumored to buy an elite player, during the transfer window, they play well which increases the odds of winning.