The Syrian civil war (Arabic: الحرب الأهلية السورية, al-ḥarb al-ʾahlīyah as-sūrīyah) is an ongoing multi-sided civil war in Syria fought between the Ba'athist Syrian Arab Republic led by Syrian President Bashar al-Assad, along with domestic and foreign allies, and various domestic and foreign forces opposing both the Syrian government and each other in varying combinations. The war is currently the second deadliest of the 21st century. The unrest in Syria, part of a wider wave of the 2011 Arab Spring protests, grew out of discontent with the Syrian government and escalated to an armed conflict after protests calling for Assad's removal were violently suppressed. The war, which began on 15 March 2011 with major unrest in Damascus and Aleppo, is being fought by several factions: the Syrian Armed Forces and its international allies, a loose alliance of mostly Sunni opposition rebel groups (including the Free Syrian Army), Salafi jihadist groups (including al-Nusra Front), the mixed Kurdish-Arab Syrian Democratic Forces (SDF), and the Islamic State of Iraq and the Levant (ISIL), with a number of countries in the region and beyond being either directly involved or providing support to one or another faction (Iran, Russia, Turkey, the United States, as well as others). Iran, Russia, and Hezbollah support the Syrian Arab Republic and the Syrian Armed Forces militarily, with Russia conducting airstrikes and other military operations since September 2015. The U.S.-led international coalition, established in 2014 with the declared purpose of countering ISIL, has conducted airstrikes primarily against ISIL as well as some against government and pro-government targets. They have also deployed special forces and artillery units to engage ISIL on the ground. Since 2015, the U.S. has supported the Democratic Federation of Northern Syria and its armed wing, the SDF, materially, financially, and logistically. Turkey has been directly involved in operations against the Syrian government since August 2016, not only participating in airstrikes against ISIL alongside the U.S.-led coalition, but also actively supporting the Syrian opposition and occupying large swaths of northwestern Syria while engaging in significant ground combat with the SDF, ISIL, and the Syrian government. Between 2011 and 2017, fighting from the Syrian Civil War spilled over into Lebanon as opponents and supporters of the Syrian government traveled to Lebanon to fight and attack each other on Lebanese soil, with ISIL and Al-Nusra also engaging the Lebanese Army. Furthermore, while officially neutral, Israel has conducted airstrikes against Hezbollah and Iranian forces, whose presence in southwestern Syria it views as a threat. International organizations have criticized virtually all sides involved, including the Ba'athist Syrian government, ISIL, opposition rebel groups, Russia, and the U.S.-led coalition of severe human rights violations and massacres. The conflict has caused a major refugee crisis. Over the course of the war, a number of peace initiatives have been launched, including the March 2017 Geneva peace talks on Syria led by the United Nations, but fighting has continued. In response to the 2019 Turkish offensive into north-eastern Syria, and the US withdrawal of forces, Russia began some efforts at mediation, and arranged for negotiations and an agreement between the Syrian government in Damascus and the SDF. Russia also negotiated an agreement to form the Second Northern Syria Buffer Zone, which made new changes to the positions of Syrian, Turkish and SDF forces.