WELLINGTON - Facebook has said it will block “praise, support and representation of white nationalism and separatism” on Facebook and Instagram from next week. The social media giant also pledged to improve its ability to identify and block material from terrorist groups.

New Zealand Prime Minister Jacinda Ardern on Thursday welcomed Facebook’s move to curb support for white nationalism on its platforms but said more needed to be done in the wake of the Christchurch mosque attacks.

Facebook users searching for offending terms will be directed to a charity which combats far-right extremism. The social network has come under pressure after a man livestreamed an attack on two mosques in New Zealand.

Facebook had previously allowed some white nationalist content it did not view as racist - including permission for users to call for the creation of white ethno-states. The company said it had deemed white nationalism an acceptable form of expression on a par with “things like American pride and Basque separatism, which are an important part of people’s identity”.

But in a blog post on Wednesday it said that after three months of consultation with “members of civil society and academics”, it found that white nationalism could not be “meaningfully separated” from white supremacy and organised hate groups.

In the wake of shootings earlier this month in New Zealand, several world leaders called on social media companies to take more responsibility for the extremist material posted on their platforms.

New Zealand Prime Minister Jacinda Ardern said social networks were “the publisher, not just the postman”, in reference to their potential liability for the material shared on them.

Facebook has previously acknowledged that a video of the attack, which left 50 people dead, was viewed more than 4,000 times before being taken down. The company said that, within 24 hours, it had blocked 1.2 million copies at the point of upload and deleted another 300,000.

A group representing French Muslims is suing Facebook and YouTube for allowing the footage to be posted on their platforms.

Other tech groups also took steps to clamp down on sharing of the video. Reddit banned an existing discussion forum on its site called “watchpeopledie” after clips of the attack were shared on the forum. Valve, which runs the Steam gaming network, said it had removed more than 100 “tributes” by users that sought to memorialise the alleged shooter.

The social media giant has unveiled tougher guidelines on hate speech for Facebook and Instagram, ruling that white nationalism and white separatism are both linked to organised hate groups and will be banned.

When making the announcement, the California-based company did not specifically reference the March 15 Christchurch atrocity that claimed 50 lives when a self-avowed white supremacist targeting Muslims opened fire in two mosques.

But Ms Ardern made it clear she believed it was a direct response to the criticism that has since been levelled at Facebook, which the accused gunman used to livestream the attack.

“Arguably these categories should always have fallen within (Facebook’s) community guidelines on hate speech,” she told reporters.  “But it’s positive that clarification has now been made in the wake of the attack here in Christchurch.”

She added “there’s more work to do” and said New Zealand would play an active role in the debate. “There are lessons to be learned here in Christchurch and we don’t want anyone to have to learn those lessons over again,” she said.

Ms Ardern said the goal was to limit harmful content “while preserving a free, open and secure internet”.

Noting that countries including Australia, Ireland and Germany were all wrestling with the issue of dealing with extremist material on social media, Ms Ardern said a global approach was needed.

“We can all promote good rules locally, but these platforms are global and I believe, therefore, that the solutions will need to be too,” she said.  “I think there would be a benefit for there being a globally coordinated response, that is what New Zealand will be looking for.”

On Tuesday Australia warned social media executives they could be jailed for failing to quickly take down extremist material.

Social media platforms “can get an ad to you in half a second,” Australia Prime Minister Scott Morrison told reporters. 

“They should be able to pull down this sort of terrorist material and other types of very dangerous material in the same sort of time frame and apply their great capacities to the real challenges to keep Australians safe,” he added.