New Zealand has awoken grieving and on high alert after a massacre at two mosques in Christchurch left 49 dead and dozens more injured in the country's worst shooting and terror attack.
While he and two other people who remain in custody have not yet been named by police and their exact roles have not been confirmed, former NSW personal trainer Brenton Tarrant online identified himself as behind the shooting that began as hundreds of worshippers gathered for prayers in the South Island city on Friday.
A 28-year-old man charged with murder is due to appear in court on Saturday, but police have declined to say if it's Tarrant.
Officials say 41 people were killed at the Masjid Al Noor mosque on Deans Avenue, before fire broke out at Linwood Masjid six kilometres away, leaving seven more dead. One other died in hospital.
Police on Saturday confirmed 42 were still being treated for injuries, including a four-year-old in critical condition.
The unprecedented event, confirmed as an act of terror by Prime Minister Jacinda Ardern, has seen the country's threat level raised to high for the first time in its history.
Public events across the nation scheduled for the weekend have been cancelled amid safety fears, with police officers and helicopters on patrol.
"There is no guarantee the risk is limited to Canterbury and we need all New Zealanders to be extra vigilant," police said in the morning.
Reports of gunfire first came at about 1.40pm on Friday, armed officers descending on the Al Noor mosque near Hagley Oval, clearing the public from the area and sending the city into lockdown.
In signs police say show a well-planned attack, army personnel were also called in to dismantle explosive devices found in a stopped car and officers were in the evening searching a house in Dunedin, 360 kilometres away, clearing nearby homes for safety.
Witnesses described bloody scenes and bodies falling to the ground as worshippers ran for doors and a shooter moved from room to room for around 20 minutes.
One man, blood strains across his shirt, told AAP he hid under a bench and pretended to stop breathing as the gunman reloaded seven times.
"He went to all the different [rooms] and he shot everyone," he said.
Notification of a shooting at the second mosque followed, before video emerged of police ramming a car and pulling out the occupant.
None of those arrested had appeared on watchlist of New Zealand or Australian security agencies, police said.
Tarrant, 28, grew up in Grafton in NSW and stated in a rambling 74-page "manifesto" posted online before the attack he had spent years planning in vengeance for deaths in Europe, before deciding on Christchurch three months ago.
The self-declared fascist said he hoped to create fear and referred to Norwegian mass murderer Anders Behring Breivik.
A post on a message board website linked to Tarrant also said the attack "against the invaders" would be live-streamed on social media.
A 17-minute video taken from a helmet camera showed a shooter in his car, arming himself, getting out of the vehicle and entering the mosque where he started shooting appeared online, authorities rushing to stop it circulating.
While calling it one of the darkest days in her country's history, Prime Minister Jacinda Ardern refused to accept it would change the character of a country that prides itself on peace, tolerance and has largely been untouched by global terror.
"We were not chosen for this act of violence because we condone racism, because we are an enclave for extremism," she said.
"We were chosen for the very fact that we are none of those things. Because we represent diversity, kindness, compassion. A home for those who share our values. Refuge for those who need it.
"And those values will not and cannot be shaken by this attack."
She is due to visit met with members of the Muslim community and first responders on Saturday.
Leaders across the world, including Queen Elizabeth, British Prime Minister Theresa May, Pope Francis and United States president Donald Trump have sent condolences and condemned the attack.
© AAP 2019