Brenton Tarrant, 28, briefly came before a district court judge, charged with murder.
Wearing a white prison suit, Tarrant appeared handcuffed and barefoot. Flanked by two police officers, he smirked when media persons photographed him during the hearing and was seen making the white power gesture. The judge said "it was reasonable to assume" more such charges would follow.
He was reprimanded without plea until his next appearance at New Zealand's High Court on April 5.
Dozens of people laid flowers at cordons near both mosques in Christchurch, which is still rebuilding after a devastating quake in 2011 that killed nearly 200 people.
New Zealand Attack: What We Know
The President of French Polynesia, Edouard Fritch sent a message of support to New Zealand Prime Minister Jacinda Ardern, following the attack in Christchurch.
The Anglican Diocese of Polynesia extended its "deepest sympathies to the Muslim community as you have once again, been a victim of this senseless act of violence resulting in the loss of life".
A Jordanian man, who did not want to be named, said he moved to New Zealand seven years ago because it was a safe place to raise his children.
The site of the terrorist attacks is sealed off in Christchurch, New Zealand, on March 16, 2019.
A licence must be obtained, however New Zealand is one of the few countries where most individual weapons don't have to be registered.More news: US bars entry of International Criminal Court investigators
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.
In light of the deadly attack, the St. Paul Police Department said they will be making more frequent visits to mosques in the city and spend more time in nearby areas.
President Donald Trump, who has a record of Islamophobic rhetoric, online behavior and policies, tweeted out his "warmest sympathy and best wishes" to the people of New Zealand. A man who claimed responsibility for the shootings left a 74-page anti-immigrant manifesto in which he explained who he was and his reasoning for the attack. He said he and others escaped by breaking through a glass door.
Although shops were shuttered and many made a decision to stay at home Saturday, bouquets of flowers piled up at a makeshift memorial near the Al Noor mosque, many accompanied with handwritten letters laden with sadness and disbelief. "I don't understand how anyone could do this to these people, to anyone".
Munir Ahmad said he prayed for the families of the victims and attackers at his Vancouver mosque this morning.More news: 'Disgusting': Politician Denounced for Blaming Mosque Shootings - Which Killed 49 - on Muslims
The video showed a man driving to the Al Noor mosque, entering it and shooting randomly at people inside. After walking back outside and shooting a woman there, he gets back in his vehicle, where the song "Fire" by English rock band "The Crazy World of Arthur Brown" can be heard blasting from the speakers. The singer bellows, "I am the god of hellfire!" and the gunman drives away.
There are about 1.5 million privately owned firearms in New Zealand, according to the most recent from 2017 data by GunPolicy.org, a global database compiled by the University of Sydney.
The last comparable mass shooting in New Zealand was nearly three decades ago, and the annual murder rate is usually around 50 people for the entire country.More news: New Zealand shooting: Brenton Tarrant called for attack on 'invader' Sadiq Khan
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