**Editors please note: this edit updates with information about arrests and the video footage posted by the gunman New Zealand is in mourning after at least one gunman opened fire in two mosques during Friday prayers (March 15).
Scores of worshippers have been killed in the city of Christchurch - in what's thought to be the country's worst-ever mass shooting.
Officials are calling it an act of terrorism.
A gunman broadcast live footage of the attack online after publishing a "manifesto" in which he denounced immigrants.
The footage is too graphic to air.
The attack drove Christchurch into lockdown as police launched a large-scale manhunt for the attacker.
Mosques across the country have been asked to close.
(SOUNDBITE) (English) NEW ZEALAND PRIME MINISTER JACINDA ARDERN, SAYING: "You may have chosen us, but we utterly reject and condemn you." "New Zealand has been chosen because we are not a place where violent extremism exists.
We reject those notions and we must continue to reject them.
This is not an enclave for that kind of behavior, for that kind of ideology.
We will and must reject it." "I am not going to let this change New Zealand's profile.
None of us should." Police say three suspects are in custody.
One of which is a man in his late twenties who has been charged with murder.
He will appear in court on Saturday (March 16).
Footage posted on social media appears to show one of the arrests.
Police say IEDs - or Improvised Explosive Devices - were found in a vehicle they stopped.
Australian Prime Minister Scott Morrison said one of the suspects is Australian.
(SOUNDBITE) (English) AUSTRALIAN PRIME MINISTER, SCOTT MORRISON, SAYING: "I can confirm that the individual who was taken into custody, I have been advised, is an Australian-born citizen," "We stand here and condemn absolutely the attack that occurred today by an extremist, right-wing, violent terrorist." The New Zealand Prime Minister says those in custody weren't on any security watch lists and that the country has been placed on its highest security threat level.