Christchurch, New Zealand — Suspected mosque shooter Brenton Tarrant made his first appearance in New Zealand court on Saturday. The Australian national is accused of killing dozens of people in a shooting rampage fueled by white nationalism and anti-immigrant ideology.

At least 50 people have died in the attack, which was New Zealand's deadliest shooting since 1990. Dozens of other victims — ranging from 2 years old to their 60s — are hospitalized.

Tarrant, with his hands in cuffs, flashed what is believed to be a white nationalist hand gesture as a judge on Saturday charged him with murder. The judge indicated Tarrant is likely to face more charges when he goes in front of the Christchurch high court on April 5, CBS News' Ben Tracy reported from the city, where the attack unfolded.

In a lengthy manifesto, the suspected gunman wrote that he plans to plead "not guilty" when the time comes but also acknowledged that what he did is a terrorist attack.

Brenton Tarrant at his appearance in the Christchurch District Court on March 16, 2019. Mark Mitchell/New Zealand Herald via Reuters

Two other suspects are in custody. The New Zealand police commissioner is expected to provide more details Sunday on those suspects.

Outside the court, Omar Nabi mourned the loss of his father, Daoud, who died in the shooting at Al Noor Mosque.

"Entering a place of prayer to shoot somebody is cowardly. It's a coward's act," he said.

Farid Ahmed, who made it out of Al Noor alive, described finding piles of bodies — the wounded and the dead.

"It was terrible," he said. "So many people, you know. Some of them were screaming."

Abdul Aziz, who survived the shooting at Linwood Mosque, said he chased the gunman down with a weapon that was left behind.

"He gets into his car and I just got the gun and threw on his window like an arrow," he said.

More than 200 miles south of Christchurch, authorities have searched a home believed to be Tarrant's. The area was evacuated as a precaution, and Australian police said Tarrant's family there is complying with investigators.

New Zealand Prime Minister Jacinda Ardern promised new gun control legislation after revealing that all five of Tarrant's weapons were purchased legally.

"Under that gun license he was able to legally acquire the guns that he held," she said. "That will give you an indication of why we need to change our gun laws."

She also met with Muslim leaders in Christchurch and promised to keep them safety.

Across the city, New Zealanders made memorials, laid down bouquets and wrote messages of unity. One read, "They will never win. Choose love."

Locals continue to leave messages and flowers for the victims outside the Botanic Gardens on March 16, 2019, in Christchurch, New Zealand. Getty

"They are trying to break down the harmony we have in New Zealand," said survivor Farid Ahmed. "They are not going to win, we will be harmonious."

On Friday, the Eiffel Tower in Paris went dark in tribute to the shooting victims. The Empire State Building in New York City also went dark, and One World Trade Center's 408-foot spire lit up with red and blue in solidarity with the Muslim community and the people of New Zealand.