Facebook's Mark Zuckerberg and US President Donald Trump are expected to be the notable absentees in a Paris summit on social media on Wednesday, where global leaders and technology company executives will seek agreement on regulations to curb violent extremism online. The summit comes two months after a gunman killed 50 people at two mosques in Christchurch in New Zealand. Original footage of the live stream was viewed about 4,000 times and 1.5 million copies of the video had been taken down within the first 24 hours before being removed from Facebook. New Zealand Prime Minister Jacinda Ardern and French President Emmanuel Macron, who will co-chair the meeting, will push for a pledge — entitled the “Christchurch Call” — that will set a common framework for stopping violent extremist content from spreading online. Ms Ardern, who has been widely acclaimed for her compassionate reaction in the aftermath of the attack and for a prompt gun law reform, said in a <em>New York Times</em> op-ed that "a terrorist attack like the one in Christchurch could happen again unless we change". “Our aim may not be simple, but it is clearly focused: to end terrorist and violent extremist content online. This can succeed only if we collaborate,” she said. “This is not about undermining or limiting freedom of speech. It is about these companies and how they operate.” Mr Zuckerberg did not confirm his attendance, despite meeting with Mr Macron on May 10 and expressing his willingness to collaborate. "Lawmakers often tell me we have too much power over speech, and frankly I agree," Mr Zuckerberg said in an op-ed on the <em>Washington Post</em>, adding that Facebook was "creating an independent body so people can appeal our decisions" about what is posted and what is taken down. He also said he would be in favour of a new set of rules that apply to all websites and tech companies, so that it's easier to stop "harmful content" from spreading quickly across platforms. Mr Macron has been promoting the idea of regulatory bodies in every European country applying a common set of rules for the removal of extremist content. The meeting is expected to tackle the thorny issue of what content should be considered harmful. France will be hosting the G7 Digital Summit this summer, which will delve into issues including digital technology and artificial intelligence. These commitments reflect the president’s desire to make France “the country that regulates” the new economy, to “reconcile technology and common good”. UK Prime Minister Theresa May, Canadian Prime Minister Justin Trudeau, European Commission President Jean-Claude Juncker, Irish Prime Minister Taoiseach Leo Varadkar, Norwegian Prime Minister Erna Solberg, Senegalese President Macky Sall, and King Abdullah II of Jordan are expected to attend. Ms Ardern said talks were "ongoing" with the US, where most of these large firms are based, but it was likely President Donald Trump would not be making the trip. She dismissed the idea that the absence of the Facebook chief and of the American president would compromise the effectiveness of the meeting. "What is much more important to me is Facebook's ultimate commitment to this call to action,'' she told media in New Zealand. "It's not about who is physically there on the day. It's what we actually generate as a result." Ms Ardern is also scheduled to hold one-on-ones with Canada's Justin Trudeau and Britain's Theresa May. The EU drew harsh criticism in April, when it amended its online copyright rules to prevent users from uploading copyrighted materials. Critics accused the European parliament committee of turning the web into a tool for surveillance and control. Striking a balance between freedom of speech and the prevention of extremism will require careful consideration of what is defined as abhorrent violent material. In her op-ed, Ms Ardern said that the aim "may not be simple," but the group rallying on Wednesday are aware of the urgency of the problem and the need to find a solution. "We can quantify the reach of this act of terror online, but we cannot quantify its impact," Ms Ardern said. Eight thousand people who saw the video called mental health support lines in New Zealand, according to the prime minister. “We need to address this … to ensure that a terrorist attack like this never happens anywhere else.”