At least 40 people have been killed and 20 seriously injured after gunmen opened fire in two mosques in the New Zealand city of Christchurch Friday, a coordinated and unprecedented attack that has shocked the usually peaceful nation.

New Zealand's Prime Minister Jacinda Ardern called the incident a terrorist attack in a Friday press conference, saying the suspects held “extremist views” that have no place in New Zealand or the world.

She confirmed that thirty people were killed when gunmen stormed the al Noor mosque on Deans Avenue.

Ten people died at the Linwood mosque on Linwood Avenue, including three who were found outside the building.

Both mosques are in Christchurch's city centre and police have placed the two locations on lockdown.

A total of 48 patients, including young children with gunshot wounds, are have been admitted to Christchurch hospital for treatment.

New Zealand Police Commissioner Mike Bush said four people have been taken into custody — three men and one woman.

Police do not believe there are any other suspects but said it was still an open investigation.

Two improvised explosive devices were attached to vehicles as part of the attack, Bush told reporters. These had been “made safe by the defence force.”

“This goes to the seriousness of the situation,” he said.

Police were still treating the incident as ongoing into Friday evening local time and urged Christchurch residents to stay indoors and monitor the police website and social media.