New Zealand has been trying to come to terms with the deaths of 49 people shot to death at two mosques during midday prayers on Friday.
One man was arrested and charged with murder.
Brenton Harrison Tarrant appeared in court on Saturday morning amid strict security and showed no emotion when the judge read him one murder charge.
The judge said “it was reasonable to assume” more such charges would follow.
Two other armed suspects were taken into custody while police tried to determine what role, if any, they played in the attack that stunned New Zealand.
It was by far the deadliest shooting in modern New Zealand history.
“It is clear that this can now only be described as a terrorist attack,” Prime Minister Jacinda Ardern said, noting that many of the victims could be migrants or refugees.
She pronounced it “one of New Zealand’s darkest days”.
Tarrant posted a jumbled, 74-page manifesto on social media in which he identified himself as a 28-year-old Australian and white supremacist who was out to avenge attacks in Europe perpetrated by Muslims.
The gunman also live-streamed in graphic detail 17 minutes of his rampage at Al Noor Mosque.
At least 48 people were wounded, some critically. Police also defused explosive devices in a car.
Christchurch Hospital chief Greg Robertson said on Saturday that seven of the 48 gunshot victims admitted after the shootings in had been discharged.
A four-year-old girl who had been transferred to an Auckland hospital was in critical condition and 11 patients who remained in Christchurch were also critically wounded.
“We have had patients with injuries to most parts of the body that range from relatively superficial soft tissue injuries to more complex injuries involving the chest, the abdomen, the pelvis, the long bones and the head,” he said.
A two-year-old boy was in stable condition, as was a 13-year-old boy.
Police did not say whether 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.
During the Saturday morning hearing, a man who was not in court was charged with using writings to incite hatred against a race or ethnicity, but it was not clear if his case was related to Tarrant’s.
Tarrant’s relatives in the Australian town of Grafton, in New South Wales, contacted police after learning of the shooting and were helping with the investigation, local authorities said.
He has spent little time in Australia in the past four years and only had minor traffic infractions on his record.
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, a city of nearly 400,000.
World leaders condemned the violence and offered condolences, with US president Donald Trump tweeting, “We stand in solidarity with New Zealand.”
New Zealand, with a population of five million, has relatively loose gun laws and an estimated 1.5 million firearms, or roughly one for every three people. But it has one of the lowest gun homicide rates in the world. In 2015, it had just eight gun homicides.
On Saturday, the prime minister said the “primary perpetrator” in the shootings was a licensed gun owner and legally acquired the five guns used.
Ms Ardern said the country’s gun laws will change as a result of the carnage, but she did not specify how.
The prime minister said the attack reflected “extremist views that have absolutely no place in New Zealand.”
Immigrants “have chosen to make New Zealand their home, and it is their home,” Ms Ardern said. “They are us.”
At the White House, Mr Trump called the bloodshed “a terrible thing” but rejected any suggestion the white nationalist movement is a rising threat around the world, saying it is “a small group of people that have very, very serious problems”.
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.