New Zealand is trying to come to terms with the deaths of 49 people shot dead at two mosques during noon prayers yesterday.
The victims were gunned down by an immigrant-hating white supremacist who apparently used a helmet-mounted camera to broadcast live footage of the massacre on Facebook.
One man was arrested and charged with murder, and two other armed suspects were taken into custody while police tried to determine what role, if any, they played in the cold- blooded attack that stunned New Zealand.
"It is clear that this can now only be described as a terrorist attack," New Zealand Prime Minister Jacinda Ardern said.
She pronounced it "one of New Zealand's darkest days".
The gunman who carried out at least one of the mosque attacks left a jumbled, 74-page manifesto that he posted on social media under the name Brenton Tarrant, identifying himself as a 28-year-old Australian and white supremacist who was out to avenge attacks in Europe perpetrated by Muslims.
He also live-streamed in graphic detail 17 minutes of his rampage at Al Noor mosque where, armed with at least two assault rifles and a shotgun, he sprayed worshippers with bullets over and over, killing at least 41 people.
Several more people were killed in an attack on the Linwood mosque in the city a short time later.
At least 48 people were wounded, some critically.
A police source said the same person was responsible for both shootings.
They gave no details about those taken into custody, except to say that none had been on any watch list.
In the aftermath, the country's threat level was raised from low to high, police warned Muslims against going to a mosque anywhere in New Zealand and the national airline cancelled several flights in and out of Christchurch.
The city's mayor has said graves are being dug for the dozens of worshippers who were killed.
Mayor Lianne Dalziel said officials were working closely with the community on the specific requirements of a large number of Muslim funerals.
World leaders condemned the violence and offered condolences.
Pakistan's Prime Minister Imran Khan and other Islamic leaders pointed to the bloodbath as evidence of rising hostility toward Muslims.
"I blame these increasing terror attacks on the current Islamophobia post-9/11 where Islam & 1.3bn Muslims have collectively been blamed for any act of terror by a Muslim," Mr Khan tweeted.
US president Donald Trump tweeted "We stand in solidarity with New Zealand" and pledged to give the country any assistance it needs.
New Zealand, with five million people, has relatively loose gun laws but few gun murders.
It is also generally considered to be welcoming to migrants and refugees.
In the wake of the slaughter, Ms Ardern said immigrants "have chosen to make New Zealand their home, and it is their home. They are us".
She said the attack reflected "extremist views that have absolutely no place in New Zealand".
At the Al Noor mosque, witness Len Peneha said he saw a man dressed in black and wearing a helmet with some kind of device on top enter the house of worship and then heard dozens of shots, followed by people running out in terror.
Mr Peneha, who lives next door, said the gunman ran out of the mosque, dropped what appeared to be a semi-automatic weapon in his driveway and fled.
Mr Peneha then went into the mosque to help the victims.
"I saw dead people everywhere. There were three in the hallway, at the door leading into the mosque and people inside the mosque," he said.
"I don't understand how anyone could do this to these people, to anyone. It's ridiculous."
Facebook, Twitter and Google scrambled to take down the gunman's video, which was widely available on social media for hours after the attack.
In the video, the killer spends more than two minutes inside the mosque spraying terrified worshippers with gunfire.
He then walks outside, where he shoots at people on the pavement.
Children's screams can be heard in the distance as he returns to his car to get another rifle. He walks back into the mosque, where there are at least two dozen people lying on the ground.
After going back outside and shooting a woman there, he gets back into his car and drives off.
The second attack took place at the Linwood mosque about 5km away.
Witness Mark Nichols said he heard about five gunshots and that a worshipper returned fire with a rifle or shotgun.
The killer also had more assault weapons in the boot of his car, along with what appeared to be explosives.
The gunman's 'manifesto' was a welter of often politically contradictory views, in which he portrayed himself as a racist and a fascist and raged against non-Westerners.