Syria: Who's backing who and why?
As Turkey enters the fourth day of an offensive in northern Syria known as operation "Olive Branch", we take a look at the different foreign actors fighting in the country, the local groups they support and their motivations for getting involved in what is an incredibly complex war:
Ankara is a longtime backer of Syrian rebels fighting president Bashar Al Assad's forces but its motivations have increasingly shifted from trying to oust the Syrian leader to reducing the dominance of Kurdish militia fighters in northern Syria. In these Kurdish militia fighters, known as the People's Protection Units (YPG), Turkey and the factions of the Free Syrian Army (FSA) it is currently fighting with have a common enemy. While the FSA factions accuse the YPG of displacing local Arabs to expand the areas of northern Syria under Kurdish control, and of secretly working with the Assad regime, Turkey views the YPG as an extension of the Kurdistan Workers' Party (PKK), which has waged a 30-year insurgency against Ankara.
Although Washington initially provided support to Syrian rebels fighting Mr Al Assad's forces in the Syrian war, as the conflict has dragged on it has increasingly narrowed its focus to stemming the extremist threat. Since 2014, the US has led an anti-ISIL coalition, with the Syrian Democratic Forces (SDF) — a militia alliance dominated by the Kurdish YPG — emerging as America's strongest ally on the ground. This month, the coalition confirmed it was working with its Syrian allies to set up a force of 30,000 personnel that will be sent to the borders of the areas in northern Syria controlled by the SDF.
Analysis: Turkish offensive adds to Syria quagmire
Tehran has supported pro-government forces in Syria since the start of the conflict, focusing much of its efforts on building, training and arming pro-Al Assad militias that directly respond to orders from Iran. Meanwhile, Iran's Lebanon proxy, Hizbollah, has sent thousands of its militants to Syria to fight on behalf of Mr Al Assad's government. Not only is the Syrian president a longtime ally of Tehran but the Iranian regime is also interested in establishing a land corridor stretching from Iran to Syria's Mediterranean coast via Iraq. This land bridge would provide Iran with a potential trade route to the West that is significantly shorter than the sea route round the Arabian peninsula.
In September 2015, Russia launched air strikes against ISIL targets in Syria, marking its first major military action outside former Soviet Union borders since the end of the Cold War. Since then Moscow has helped Mr Al Assad's government to dramatically turn around its fortunes, with Damascus retaking control of most of the country under Russian air cover. Moscow wants to keep Mr Al Assad — its main Middle East ally — in power to ensure its continued military influence in the region. But unlike Iran it has primarily focused on supporting government forces rather than pro-Al Assad militias.