WELLINGTON, New Zealand — A gunman opened fire on two mosques in central Christchurch, New Zealand, on Friday, killing multiple people, the police said.
The police said one person was in custody, but they were unsure if there were other people involved. The country’s police commissioner, Mike Bush, warned Christchurch residents to stay indoors and told anyone thinking of visiting a mosque in New Zealand today to not go.
“This is and will be one of New Zealand’s darkest days,” New Zealand’s prime minister, Jacinda Ardern, said at a news conference after the shootings.
The national public broadcaster Radio New Zealand reported that shots were fired at a mosque near Hagley Park, and that a second mosque on Linwood Avenue, also in Christchurch, was attacked.
Ardern said at the Friday afternoon news conference, ‘‘what has happened here is an extraordinary and unprecedented act of violence.’’
She said while many people affected may be migrants or refugees ‘‘they have chosen to make New Zealand their home and it is their home. They are us. The person who has perpetuated this violence against us is not.’’
While the details of the shooting were still unclear, one witness reported that many people were killed at a mosque.
‘‘I saw dead people everywhere. There were three in the hallway, at the door leading into the mosque, and people inside the mosque,’’ witness Len Peneha said. ‘‘It’s unbelievable nutty. I don’t understand how anyone could do this to these people, to anyone. It’s ridiculous.’’
Peneha said he saw a man dressed in black enter the Masjid Al Noor mosque in central Christchurch at about 1:45 p.m. and then heard dozens of shots, followed by people running from the mosque in terror.
Peneha, who has lived next door to the mosque for about five years, said the gunman ran out of the mosque, dropped what appeared to be a semiautomatic weapon in Peneha’s driveway, and fled. Peneha said he then went into the mosque to try and help.
The New Zealand Herald said a gunman at one mosque recorded his actions and posted the video to YouTube.
“This is an evolving incident and we are working to confirm the facts, however we can confirm there have been a number of fatalities,” Bush said in a statement. “We ask all mosques nationally to shut their doors, and advise that people refrain from visiting these premises until further notice.”
Another witness, Mohammad Isam, a Bangladeshi journalist, posted a video of members of Bangladesh’s national cricket team who he said escaped the attack.
The video showed several men in the team’s jersey walking briskly through a park with the message, “Bangladesh team escaped from a mosque near Hagley Park where there were active shooters. They ran back through Hagley Park back to the Oval,” referring to the nearby cricket ground.
Analyst Shrinivas Chandrasekeran, traveling with the team, said on Twitter, said ‘‘Just escaped active shooters. Heartbeats pumping badly and panic everywhere.’’
Ardern confirmed that one suspect was in custody but ‘‘there could be others involved.’’
The website Stuff reported that the police had cleared nearby Cathedral Square, the site of a rally to fight climate change.
Reports of the shooting happened as young protesters were gathering in Christchurch and cities around the world to demand action on climate change. A day earlier, the country’s minister for climate change, James Shaw, 45, told the police that he was grabbed and hit on the street in the country’s capital of Wellington.
Christchurch, with about 388,000 residents, is the biggest city on New Zealand’s South Island, hugging the Pacific Ocean coast.
There hasn’t been a mass shooting in New Zealand since 1990, when a man killed 13 people, including two 6-year-olds, after a dispute with his neighbor in the seaside town of Aramoana.
That shooting led to tightened gun laws, including restrictions on “military style semi-automatic weapons.”
Gun owners must be licensed, a process that includes a review of criminal activity and mental health, attendance at a safety program, an explanation of how the gun would be used, a residence visit to ensure secure storage, and testimonials from relatives and friends.
Murders are rare in New Zealand, and gun deaths even rarer. There were 35 murders countrywide in 2017. Since 2007, gun homicides have been in the single digits each year except 2009, when there were 11.
But there are plenty of guns. There were 1.2 million registered firearms in a country of 4.6 million people in 2017, according to the Small Arms Survey, a Swiss nonprofit.
Much like in the United States, gun laws remain a source of heated political debate.
US Ambassador Scott Brown, a former US Senator from Massachusetts, offered his condolences.
“We’re heartbroken over the events in Christchurch today. We stand with our Kiwi friends and neighbors and our prayers are with you,’’ Brown said on Twitter.Material from the Associated Press and Bloomberg News was used in this report. Danny McDonald of the Globe Staff contributed.