Forty-nine killed in New Zealand terror attack on two mosques

“It is clear that this can now only be described as a terrorist attack," she said.

New Zealand's national security threat level was lifted from low to high and Air New Zealand cancelled all turboprop flights out of Christchurch on Friday night.

Ms Ardern said the attack appeared to have been "well-planned", with two bombs attached to cars, which had been defused by police.

Four people were arrested, three of whom were connected to the attack. Ms Ardern said one of those arrested was Australian-born and had extreme views. It was her understanding they were not on watch lists.

“At this stage the Government has no reason to believe there are any other suspects,” she said.

Ms Ardern said the attackers had extremist views and had no place in New Zealand, "and in fact have no place in the world".

"We were not chosen for this act of violence because we condone racism, because we are an enclave for extremism. We were chosen for the very fact that we are none of those things."

Prime Minister Scott Morrison confirmed one of the suspects taken into custody was Australian, describing the act as a “vicious, murderous” act of “right-wing” terror.

Tarrant filmed himself for 16 minutes as he sprayed victims with bullets during Friday prayers at the Masjid Al Noor mosque.

He published an online link to a lengthy "manifesto", which a security analyst described as “straight out of the white supremacist playbook”.

The manifesto said the attack was revenge for the "invaders in European lands" and "we must ensure the existence of our people, and a future for white children”.

He also wrote that he began planning the attack “roughly two years in advance”, and chose the final location three months prior to the attack.

Twitter has shut down a user account in Brenton Tarrant’s name.

It was not immediately clear whether Tarrant was involved in far-right neo-Nazi groups in Australia.

Tarrant, who attended Grafton High School before was reportedly dedicated to fitness and ran free athletic programs for children.

Former employer Tracey Gray told Channel Nine that Tarrant had been working as a personal trainer for “a good number of” years at the Big River Squash and Fitness Centre before leaving for New Zealand in 2012.

“Somewhere along the lines, experiences or a group have got a hold of him,” she said.

Worshippers were targeted at two central Christchurch mosques - Masjid Al Noor in Deans Ave at 1.40pm, where 30 people were killed and Linwood Masjid shortly afterwards where 10 people were killed.

The Bangladesh cricket team were about to enter the Masjid Al Noor, near where they were due to play their final Test match of their tour of New Zealand, moments before the attack.

None of the players were harmed. The team tweeted all members of the team had made it safely back to their hotel.

The third test match between the Black Caps and Bangladesh was cancelled and the team was planning to fly home as soon as possible.

Among the victims of the massacre was a four-year-old boy who was reportedly in a critical condition.

Farhaan Farheez was in the Linwood Mosque praying with about 100 others when the shooting started.

"I didn't know what a gun sounded like. It is customary when we are praying not to pay attention to the outside world,” he told Stuff.co.nz. “Gunshots kept happening and people kept praying."

"I saw two females and four or five males dead and the rest were severe casualties ... The whole mosque was filled with blood and dead bodies. It was like a battlefield."

The city immediately went into lockdown with police urging residents to stay indoors.

“We ask all mosques nationally to shut their doors,” New Zealand Police tweeted.

The Civil Aviation Authority declared Christchurch City a controlled air space and a crisis meeting of national security agencies was held in Wellington.

In the video, Tarrant says: "Let's get this party started," as he starts his car and begins to travel to the mosque.

He pauses and says: "Remember lads, subscribe to PewDiePie."

PewDiePie is the online persona for comedian and professional video-game player Felix Kjellbergone. The phrase "subscribe to PewDiePie" (pronounced pew-de-pai) has become a meme in alt-right and neo-Nazi forums in recent months because Kjellberg is at risk of losing his number-one spot on YouTube to an Indian music label T-Series.

The alt-right claim Kjellberg is one of their own due to a checkered history that includes, among other things, using the N-word while broadcasting live and including anti-Semitic imagery in his videos.

Kjellberg said he was "absolutely sickened" to learn his name was uttered before the attack.

Weapons sighted in the video include two full-auto military-style assault rifles, one semi-automatic shotgun, one pump-action shotgun and two unidentified long arms.

He opened fire several times before throwing the gun to the ground.

Tarrant then picked up another gun and continued to fire, shooting one person as they desperately attempted to crawl away.

He then gets into another room where he fires at people trying to hide from him.

Several bodies can be seen in the video.

Once outside, the man shoots again down the street.

One woman can be seen lying on the road yelling. "Help me, help me."

The shooters' rifles had "Alexandre Bissonette" and "Luca Traini" written on them - the names of mosque shooters in Italy and Canada.

Mohan Ibrahim was one of 200 people in Masjid Al Noor mosque when he heard shots being fired.

"At first we thought it was an electric shock but then all these people started running,” he told the New Zealand Herald.

A man, who would not give his name, said he was praying in the Masjid Al Noor when he heard the shooting start.

He managed to escape, but outside saw his wife lying dead on the footpath.

"My wife is dead," he said, wailing. He was supported by other Muslim men who prayed for him.

Another man said he saw children being shot.

New Zealand’s last mass shooting was the 1990 Aramoana massacre, in which 13 people were murdered as well as the killer David Gray.

Muslims Australia said the massacre was “a product of the ever-increasing Islamophobia and marginalisation of Muslims”. (It) is a reminder to all concerned, including political leaders and media commentators, of the horrific consequences that an atmosphere of hate and division can lead to,” it said in a statement.

The Department of Foreign Affairs was working with New Zealand authorities to determine whether any Australians have been killed in the attack.