The leader of an Austrian far-right group has had his YouTube accounts shut down, the website's owner Google confirmed on Tuesday. Martin Sellner is the leader of the Identitarian Movement Austria, described by the country's intelligence services as "agents of modern right-wing extremism". His Facebook and Instagram accounts were suspended in 2018, and Twitter pulled the plug on his account last week for violating policies against violent extremism. "Google/YouTube can confirm that the channels by Martin Sellner were terminated in line with our Hate Speech policies," Google said in a statement sent to AFP. However it said it could not provide further details on the background to the ban for legal reasons. Last year, Sellner admitted he had been contact with Brenton Tarrant, an Australian white supremacist who murdered 51 Muslims in a New Zealand mosque. Tarrant made a 1,500-euro ($1,700) donation to Sellner in January 2018. Sellner and the Identitarians are proponents of the far-right "Great Replacement" conspiracy theory according to which white Europeans are being deliberately supplanted by non-white immigrants. Tarrant's manifesto was also titled "The Great Replacement". The Identitarians are also known for anti-immigrant stunts such as a 2017 incident in which members gained access to the roof of the Turkish embassy in Vienna, unfurling a banner addressing Turkish President Recep Tayyip Erdogan reading: "Erdogan, take your Turks home." The ban on Sellner comes as social media giants are being scrutinised for what activists say is their failure to take responsibility for misinformation and hate speech on their platforms. Hundreds of advertisers including big-name consumer brands and Britain's main opposition Labour party have recently suspended advertising with Facebook as part of the #StopHateForProfit" campaign. jsk/jxb