New Zealand attack - live updates: Suspected gunman appears in court as Prime Minister Ardern promises ‘gun laws will change’

New Zealand Prime Minister Jacinda Ardern says 40 people have died and more than 20 people were seriously injured in the mosque shooting

Ardern says 30 of the fatalities occurred at the Al Noor mosque in central Christchurch. Seven of the dead were inside the suburban Linwood Masjid Mosque and three died outside the same mosque.

Ardern says New Zealand has been placed on its highest security threat level.

She says that the four people in police custody held extremist views, but had not been on any police watchlists.

She confirmed that one is an Australian citizen.

Ardern says "this can only be referred to as a terror attack".

She refers to multiple attackers and says explosive devices were attached to their vehicles, but says she cannot "give specifics about who was directly involved at each mosque".

Ardern wraps up the news conference in Wellington saying she is planning to head to Christchurch "as early as I can".

The third Test match between New Zealand and Bangladesh has been postponed.

The match was due to take place in Christchurch, and the Bangladesh squad was visiting the Al Noor mosque as the attack unfolded. No players were harmed.

Ardern said earlier that the national security threat level has been lifted from low to high after the deadly shootings at two mosques. 

The security threat level is now at the second-highest level. She said authorities had no reason to believe there were more suspects, but "we are not assuming that at this stage." 

The UK stands with New Zealand, foreign secretary Jeremy Hunt has tweeted:

Australian Senator Fraser Anning, an independent formerly of the right-wing nationalist One Nation party, is being widely condemned for issuing a statement criticising "Muslim immigration" in the wake of the Christchurch attack.

Anning posted a press release and a number of tweets on the subject, including one in which he spouts that "the real cause of bloodshed on New Zealand streets today is the immigration program that allowed Muslim fanatics to migrate to New Zealand in the first place".

Speaking to news.com.au, a media adviser for Anning denied there had been any backlash to the statement, though any evidence of Anning himself sharing the press release has now been deleted.

Some 48 people, including children, are being treated in Christchurch Hospital after shootings at two mosques in the city on Friday, New Zealand health authorities said.

Wounds range from minor to critical, they said.