New Zealand's police commissioner said on Friday 49 people were killed in Christchurch at two mosques and one man of four people arrested had been charged with murder.
As many as 41 people died at one mosque, seven at another and one person died in hospital, Mike Bush told reporters, describing the attack as a "very well-planned event".
The man charged with murder is in his late 20s and should appear in Christchurch court on Saturday, Bush added.
This was the country’s worst-ever mass shooting which Prime Minister Jacinda Ardern condemned as terrorism.
A gunman broadcast online live footage of the attack on one mosque in the city of Christchurch, mirroring the carnage played out in video games, after publishing a “manifesto” in which he denounced immigrants.
New Zealand was placed on its highest security threat level, Ardern said, adding that four people in police custody, three men and one woman, held extremist views but had not been on any police watchlists.
The visiting Bangladesh cricket team was arriving for prayers at one of the mosques when the shooting started but all members were safe, a team coach told Reuters.
“It is clear that this can now only be described as a terrorist attack,” Ardern said.
The video footage widely circulated on social media, apparently taken by a gunman and posted online live as the attack unfolded, showed him driving to one mosque, entering it and shooting randomly at people inside.
Worshippers, possibly dead or wounded, lay huddled on the floor, the video showed. Reuters was unable to confirm the authenticity of the footage.
One man who said he was at the Al Noor mosque told media the gunman was white, blond and wearing a helmet and a bulletproof vest. The man burst into the mosque as worshippers were kneeling for prayers.
“He had a big gun ... he came and started shooting everyone in the mosque, everywhere,” said the man, Ahmad Al-Mahmoud. He said he and others escaped by breaking through a glass door.
An anonymous post on Friday on the discussion site 8chan, known for a wide range of content including hate speech, said the writer was going to “carry out an attack against the invaders”, and included links to a Facebook live stream, in which the Friday shooting appeared, and a manifesto.
The manifesto cited “white genocide”, a term typically used by racist groups to refer to immigration and the growth of minority populations, as his motivation.
The Facebook link directed users to the page of a user called brenton.tarrant.9.
A Twitter account with the handle @brentontarrant posted on Wednesday images of a rifle and other military gear decorated with names and messages connected to white nationalism. What looked like the same weapons appeared in the livestream of the mosque attack on Friday.
Ardern said 30 people were killed at the Al Noor mosque, the city’s main mosque, and another 10 at a mosque in the suburb of Linwood. It was not immediately clear if the attacks were carried out by the same man.
“This is one of New Zealand’s darkest days,” Ardern said.
Australian Prime Minister Scott Morrison said one of the men in custody was Australian.
All mosques in New Zealand had been asked to shut their doors, police said.
The killings were condemned by political and Islamic leaders across Asia.
“Indonesia strongly condemns this shooting act, especially at a place of worship while a Friday prayer was ongoing,” Foreign Minister Retno Marsudi said in a statement.
She was earlier cited by media as saying six Indonesians had been inside one mosque when the attack occurred, with three managing to escape and three unaccounted for.
In Muslim-majority Malaysia, Anwar Ibrahim, the leader of the biggest party in its ruling coalition, said: “I am deeply saddened by this uncivilized act, which goes against humanistic values and took the lives of civilians.”
Muslims account for just over 1 percent of New Zealand’s population, a 2013 census showed.
‘Firing went on and on’
The online footage, which appeared to have been captured on a camera strapped to the gunman’s head, showed him driving as music played in his vehicle. After parking, he took two guns and walked a short distance to the mosque where he opened fire.
Over the course of five minutes, he repeatedly shot worshippers, leaving more than a dozen bodies in one room alone. He returned to the car during that period to change guns, and went back to the mosque to shoot anyone showing signs of life.
One man, with blood still on his shirt, said in a television interview that he hid from the gunman under a bench and prayed that he would run out of bullets.
“I was just praying to God and hoping our God, please, let this guy stop,” Mahmood Nazeer told TVNZ.
“The firing went on and on. One person with us had a bullet in her arm. When the firing stopped, I looked over the fence, there was one guy, changing his gun.”
The video shows the gunman then driving off at high speed and firing from his car. Another video, taken by someone else, showed police apprehending the gunman on a pavement by a road.
Police said improvised explosive devices were found with a vehicle they stopped. The gunman’s video had shown red petrol canisters in the back of his car, along with weapons.
The Bangladesh cricket team is in Christchurch to play New Zealand in a third cricket test starting on Saturday.
“They were on the bus, which was just pulling up to the mosque when the shooting begun,” Mario Villavarayen, team strength and conditioning coach, told Reuters in a message. “They are shaken but good.”
The third cricket test was cancelled, New Zealand Cricket said later.
Violent crime is rare in New Zealand and police do not usually carry guns.
Before Friday, New Zealand’s worst mass shooting was in 1990 when a gun-mad loner killed 13 men, women and children in a 24-hour rampage in the tiny seaside village of Aramoana. He was killed by police.