number of mob attacks on Muslims. In Sri Lanka, similarly, rumours on social media sparked antiMuslim mob attacks in Sri Lanka last year, which have re-ignited in the wake of Easter Sunday church and hotel bombings by ISIS in April 2019. Yet social media can play a positive role too. Through circulating valuable information, it can provide a public service. Many platforms monitor the movements of militaries and insurgents, such as Libya’s ‘SafePath’ Facebook group, which directs users to avoid certain roads due to fighting. Civilians can be similarly guided to humanitarian aid locations. Dialogue across social divides can be facilitated by social media, shifting attitudes and promoting understanding among groups that may not otherwise communicate with each other, reverse-engineering conditions of enmity and violence. With low opportunity costs for acquiring, tailoring, and circulating information, social media is crucial to bearing and sharing witness, to documenting violations of international humanitarian law or human rights, and widely broadcasting content to provoke action among human rights groups and international organizations. Social media can play a role in ending inaction and impunity, securing accountability and reparation for violations. No society can prevent violence or build peace without accounting for the role of social media – least of all, those populating the upper reaches of the Peoples under Threat table, where the risk of mass killing has become pressing or critical. But even in states where the imminent risk is much lower and which do not therefore appear on the list (including those in Western Europe and North America), social media penetration has quickly created effectively unregulated platforms for the dissemination of hatred against minorities. Longstanding support for freedom of expression has been subverted into widespread societal tolerance for the expression of violent extremism. Governments have universally failed to live up to their obligations not just to protect freedom of expression but also to prohibit any ‘advocacy of national, racial or religious hatred that constitutes incitement to discrimination, hostility or violence’, as required by the International Covenant on Civil and Political Rights (Article 20(2)). Peoples under Threat identifies those country situations around the world where communities face the greatest risk of genocide, mass killing, or systematic violent repression. Based on current indicators from authoritative sources (see box), Peoples under Threat 4 has been compiled every year since 2005 to provide early warning of potential future mass atrocities. Peoples under Threat highlights 20 situations with pressing risks – states either at the top of the index or those swiftly rising. It is estimated that these will account for the vast majority of civilians who are likely to be killed over the following year. Peoples at greatest risk Syria retains its highest-ranked position in the Peoples under Threat index as signs of President Assad’s military ‘victory’ grow ever clearer. Syria’s largest cities are now under government control, although significant territory remains in the hands of predominantly Islamist opposition fighters as well as an alliance of Kurdish and Arab militias, the Syrian Democratic Forces. In March 2019, Kurdish forces captured the eastern village of Baghouz, the last populated area in Syria controlled by ISIS. Backed by Russia, Iran and numerous Shi’a militias, government forces are closing in on Idlib province, the final opposition holdout. While all sides have committed widespread atrocities, the vast majority of civilian deaths in Syria have come at the hands of the regime, which along with Russia continues to bomb hospitals and other civilian infrastructure. While figures are impossible to verify, more than 500,000 people are estimated to have been killed and 12 million more displaced inside Syria or abroad. Social media has played an unprecedented role in the Syria conflict, with all sides exploiting online platforms to communicate competing narratives, recruit fighters, fundraise and document or deny human rights abuses. Cycles of deadly violence are unrelenting in Somalia. Civilians face serious abuses, including targeted and indiscriminate killings, forced recruitment and evictions, and sexual violence. AlShabaab has used Twitter and Facebook as tools to broadcast propaganda and recruit supporters in an environment where mobile phone penetration has been rising steadily in recent years. The majority of its bombing, shelling and gunfire attacks on politicians, other state officials, joint forces and civilians are in Mogadishu and the adjacent Lower Shabelle region, but also often take place in Jubaland and Puntland. Countervailing military operations by Somali government forces, African Union Mission in Somalia (AMISOM) troops and other foreign forces, including escalating airstrikes by the United States Peoples under Threat 2019