Police said they have arrested three men and a woman, and while they don't think there are any armed offenders still at large, they can't be sure the danger has passed or the incident is confined to Christchurch.
The Aramoana shooting led to changes in the nation's gun laws, and a review that was already underway in 1995, gained more momentum after shootings in Scotland and Australia.
"New Zealand Police alerted us to a video on Facebook shortly after the livestream commenced and we quickly removed both the shooter's Facebook and Instagram accounts and the video", a Facebook spokeswoman told CNN.
He live-streamed footage of himself going room-to-room, victim to victim, shooting the wounded from close range as they struggled to crawl away in the main Christchurch mosque.
Police said 41 people died at the Deans Avenue mosque and seven died at the Linwood Avenue mosque.
Western leaders from Donald Trump to Angela Merkel expressed solidarity with the people of New Zealand and deplored what the White House called an "act of hate".
"Not at all, this is New Zealand man, multicultural you know. They may even be refugees here", Prime Minister Ardern reportedly said.
Brenton Harrison Tarrant, a 28-year old Australian citizen, appeared in a Christchurch District Court and was remanded without a plea until his next scheduled appearance in the South Island city's High Court on April 5.
Toronto's Deputy Mayor Denzil Minnan-Wong said the attack has left many people in the city's Muslim community "shaken".
Semi-automatic AR-15s on sale at a Utah gun range Semi-automatic AR-15s on sale at a Utah gun range
A man who could not find out information about what happened to his father and two brothers pushed through police barricades at one of the cordons in an effort to get closer.
Ambulance officers transfer a boy to Dunedin Public Hospital, New Zealand, Nov. 14, 1990, after he had been shot in Aramoana.
"At first we thought it was an electric shock but then all these people started running". "And I'm getting sick and exhausted of that particular scenario playing itself out over and over again, where they keep silent when one of their people do something, but when... whenever they're able to gain a sort of political capital for themselves, all of a sudden they're chatty".
"Attacking people during prayers is absolutely appalling, and Canada strongly condemns today's shootings in New Zealand", he wrote on Twitter. Friday is Islam's holy day.
Jordan's King Abdullah II tweeted that "the heinous massacre against Muslims praying in peace in New Zealand is an appalling terrorist crime".
Iran's Foreign Minister Mohammad Javad Zarif said bigotry in Western countries contributed to the attacks on Muslims in New Zealand.
"There were bodies all over", he said. The minimum legal age to buy a firearm is 16.
Multiple people were killed in mass shootings at two mosques full of people attending Friday prayers, as New Zealand police warned people to stay indoors as they tried to determine if more than one gunman was involved.