At least one gunman who targeted crowded mosques in the New Zealand city of Christchurch killed a number of people on Friday, police said, with Prime Minister Jacinda Ardern describing the shooting as "one of New Zealand's darkest days".
The mosques were packed with worshippers gathering for Friday afternoon prayers, and members of the Bangladesh cricket team were arriving when the shooter opened fire, reports AFP.
Police commissioner Mike Bush said that "he can't say how many" casualties have taken place but the local media placed the death toll at 27.
New Zealand police said four people, including one woman, were taken into custody in connection to shootings at the two mosques.
Multiple improvised explosive devices, that were found on vehicles after the shootings, were defused, police said.
Bush did not confirm if authorities were treating the shooting as a terror attack but said that: "It does not get more serious than this."
He refused to provide any details regarding the situation but warned against assuming that the danger had passed.
"We are not aware of other people, but we cannot assume there are not others at large," he told the press.
The South Island city was placed in lockdown as police hunted for an “active shooter".
“A serious and evolving situation is occurring in Christchurch with an active shooter,” police said in a statement. “Police are responding with its full capability to manage the situation, but the risk environment remains extremely high.”
Police urge people to stay indoors and not to visit mosques "anywhere in New Zealand".
Unconfirmed reports said the shooter was wearing military-style clothing. According to the BBC, an unverified video has emerged on social media that was reportedly recorded by the attacker during the shooting.
'Unprecedented act of violence,' New Zealand PM says of shooting
New Zealand Prime Minister Jacinda Ardern described the incident as an "unprecedented act of violence".
"I would describe it as an unprecedented act of violence. An act that has absolutely no place in New Zealand. This is not who we are," she said in a press conference.
"It I can tell you now this is and will be one of New Zealand's darkest days."
Ardern confirmed that one person had been taken under custody.
"Migrants and refugees have chosen to make New Zealand their home and it is their home. For the person who perpetuated this violence it is not."