NSW Police have addressed the media for a second time this afternoon following a mass shooting in Christchurch.
Police have confirmed that four people are in custody, believed to be three men and one woman.
No conclusive motivation has been declared for the attack, with police still looking at the circumstances.
"It doesn't get any more serious in this country," NZ Police Commissioner Mike Bush said.
"We cannot assume that there are not others at large.
"We are also setting up a facility as we must because this is absolutely tragic and so many people will be affected."
It was noted that locations are still in lockdown, so there is not much information on the casualties of the two attacks.
"We don't have the identities of the people who have died as yet as those facilities are still in lockdown," Comm Bush said.
"We have multiple fatalities. At this point, I can't say how many but it is significant.
"They occurred in two locations - two mosques.
"This is requiring every police emergency resource that we have available."
Footage has been circulating online of the attack, as one of the gunmen livestreamed the shooting on social media.
This footage has been reposted and shared, and is very graphic.
"Footage is very disturbing and shouldn't be in public domain," Comm Bush said.
"We are doing everything we can to remove it."
Commissioner Bush also noted the huge effort by police in securing the areas.
"There have been absolute acts of bravery," he said.
"Let's not assume the danger is gone."
There were reports of car bombs near the shooting locations, with the Commissioner confirming that these have been dealt with by police.
"Cars have been made safe by defence force."
It was noted that there were a "number" of IEDs (improvised explosive devices) that have been made safe, however a specific amount has not been named.
Gunshots were heard after 1pm local time in the Hagley Park area inside a mosque.
Local schools, shopping centres and hospitals were placed in lockdown, with people urged to stay inside as the 'active shooter' situation further developed.
Then reports emerged of a second attack, with a mosque in Linwood the second location.
The Bangladesh cricket team were inside one of the mosques, but all members managed to escape safely.
New Zealand Cricket has since tweeted that an upcoming test at Hagley Oval has been cancelled.
More to come.