Police say 49 people have been killed and dozens injured in shootings at twomosques in the New Zealand city of Christchurch when at least one gunman opened fire on worshippers.
A man, one of several to be detained, has been charged with murder, police say. One of the massacres was streamed live on social media.
It's the country's worst ever mass shooting and has been condemned internationally.
“This is one of New Zealand’s darkest days,” said Prime Minister Jacinda Ardern. “Clearly what has happened here is an extraordinary and unprecedented act of violence.”
“There is no place in New Zealand for such extreme acts,” she said, describing it as a terrorist attack.
Most of the victims are said to have been killed at the Al Noor mosque, the main mosque in the city on New Zealand's South Island, with several more people killed at a mosque in the suburb of Linwood.
Some 48 people, including children, are being treated at Christchurch hospital, New Zealand health authorities have said. Wounds range from minor to critical, they said.
Reports have suggested that those inside the mosques included refugees and migrants.
Four people – three men and one woman – were taken into custody, police say, but they are not sure if others are involved. The prime minister said they were not on a terror watch-list.
Police say a man in his late twenties has been charged with murder. They have added that they are not looking for further suspects.
Australia's Prime Minister Scott Morrison has confirmed that one of the suspects was Australian-born.
He described the massacre as a "vicious, murderous attack" on people of faith, carried out by "an extremist, right-wing violent terrorist".
New Zealand police say their Australian colleagues had no information on the suspects.
The shooting happened on Friday afternoon, local time, during Friday prayers. The mosques, a few kilometers apart, are close to Christchurch city center.
Eyewitnesses said a white man dressed in a military-style, camouflage outfit and carrying an automatic rifle had started shooting people at random in the Al Noor mosque. Some have described horrific scenes, with the shooting carrying on for several minutes and people being shot outside as well as inside the mosque.
"I did not see who was shooting but I saw that some people were running out through my room where I was in and also I saw some people had blood on their body and some people were limping. At that moment I realized it was really serious," said one survivor, Mohamed Nazir.
There was a lucky escape for the Bangladesh cricket team. It was arriving for prayers at the Al Noor mosque when the shooting happened, one of the team’s coaches told Reuters, adding that all members were safe. “They are shaken but good,” Mario Villavarayen said.
A test match between New Zealand and Bangladesh due to start on Saturday in Christchurch has been cancelled in the wake of the shootings.