Christchurch, New Zealand • At least 49 people were killed in mass shootings at two mosques full of worshippers attending Friday prayers in an attack broadcast in horrifying, live video by an immigrant-hating white supremacist wielding at least two assault rifles and a shotgun.

One man was arrested and charged with murder, and two other armed suspects were taken into custody while police tried to determine what role they played.

"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.”

News of the shootings quickly spread and has shaken Utah’s Muslim community.

“It’s tragic,” said Shuaib Din, imam at the Utah Islamic Center in Sandy, “and it should be alarming to all of us, the rise in hate crimes. Not just to Muslims, but to different minorities and ethnicities and people of different color and creed.”

Din said the shooting “has been worrisome to people in our congregation,” and he has received several calls from people “who were definitely nervous.”

However, the center will continue with its regular Friday service as planned. “We will remember them in our prayers,” he said, of the victims, “and at the same time, look at our own security.”

Din hoped leaders in Utah and the U.S. would speak out and condemn the “act of hate and terror."

“When a (Christian) church burns Muslims should be sad,” he said, "and when a mosque burns Christians should be sad.”

The cold-blooded attack shocked people across the nation of 5 million people, a country that has relatively loose gun laws but few gun homicides and is so peaceful police officers rarely carry firearms. New Zealand is also generally considered to be welcoming to migrants and refugees.

The gunman behind at least one of the mosque shootings left a 74-page manifesto that he posted on social media under the name Brenton Tarrant, identifying himself as a 28-year-old Australian and white nationalist who was out to avenge attacks in Europe perpetrated by Muslims.

Using what may have been a helmet camera, he livestreamed to the world in graphic detail his rampage at Christchurch's Al Noor Mosque, where at least 41 people were killed as he sprayed them with bullets over and over, sometimes firing at victims he had already cut down. Several more worshippers were killed in an attack on second mosque in the city a short time later.

At least 48 people were wounded, some critically, authorities said.

Police did not immediately say whether the same person was responsible for both shootings. They did not identify those taken into custody and gave no details about them except to say that none had been on any watch list.

While there was no reason to believe there were any more suspects, the prime minister said the national threat level was raised from low to high. Police warned Muslims against going to a mosque anywhere in New Zealand. And Air New Zealand canceled several flights in and out of Christchurch.

Police said the investigation extended 240 miles to the south, where homes in Dunedin were evacuated around a “location of interest.” They gave no details.

World leaders condemned the attacks and offered condolences. Pakistan's Prime Minister Imran Khan and other Islamic leaders pointed to the bloodshed and other such attacks as evidence of rising hostility toward Muslims.

"I blame these increasing terror attacks on the current Islamophobia post-9/11 where Islam & 1.3 bn Muslims have collectively been blamed for any act of terror by a Muslim," Khan tweeted.

New Zealand's prime minister said that immigrants and refugees "have chosen to make New Zealand their home, and it is their home. They are us." As for the suspects, Ardern said, they harbor "extremist views that have absolutely no place in New Zealand."

Witness Len Peneha said he saw a man dressed in black and wearing a helmet with some kind of device on top enter the Al Noor mosque and then heard dozens of shots, followed by people running out in terror.

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. He said he then went into the mosque to try 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."

In the video that was livestreamed, the gunman spends more than two minutes inside the mosque spraying terrified worshippers gunfire. He then walks outside, where he shoots at people on the sidewalk. Children's screams can be heard in the distance as he returns to his car to get another rifle. The gunman 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 in his car, where the song "Fire" by the English rock band The Crazy World of Arthur Brown can be heard blasting. The singer bellows, "I am the god of hellfire!" and the gunman drives away.

The second attack took place at the Linwood mosque about 5 kilometers (3 miles) away.

Mark Nichols told the New Zealand Herald that he heard about five gunshots and that a prayer-goer returned fire with a rifle or shotgun. Nichols said he saw two wounded people being carried out on stretchers past his automotive shop.

Based on the video, the attacker was at the scene of the first mosque for about 10 minutes, and police did not arrive until after that.

The footage showed he was carrying a shotgun and two fully automatic military assault rifles, with an extra magazine taped to one of the weapons so that he could reload quickly. He also had more assault weapons in the trunk of his car, along with what appeared to be improvised explosives.

The gunman said he was not a member of any organization, acted alone and chose New Zealand to show that even the most remote parts of the world are not free of "mass immigration."

Last year, New Zealand's prime minister announced that the country would boost its annual refugee quota from 1,000 to 1,500 starting in 2020. Ardern, whose party campaigned on a promise to take in more refugees, called it "the right thing to do."

Christchurch is home to nearly 400,000 people and is sometimes called the Garden City. It has been rebuilding since an earthquake in 2011 killed 185 people and destroyed many downtown buildings.

Before Friday's attack, New Zealand's deadliest shooting in modern history took place in the small town of Aramoana in 1990, when a gunman killed 13 people following a dispute with a neighbor.