Washington first deployed troops in northeast Syria in 2014 as part of a coalition to combat the Islamic State group.
Russia has militarily backed the government of President Bashar al-Assad since 2015, but did not deploy its forces in the northeast until late last year, following a Turkish invasion against Kurdish fighters.
Turkey’s offensive in October was spurred in part by US President Donald Trump who said he was pulling his forces out of border areas in the northeast.
Feeling abandoned by their erstwhile allies in the anti-IS battle, the Kurds turned to Damascus and Moscow to prevent a deeper incursion into their region.
Since then, Russian soldiers and American troops have rubbed shoulders in Kurdish-held territories, where their patrols cross paths regularly, flags fluttering simultaneously on opposite sides of the road.
But the presence of Russian troops has also helped US forces avoid a face-off with Syrian regime forces.
Syria is the only country in decades to have seen both American and Russian forces on the ground at the same time.
In February 2018, US-led coalition strikes killed dozens of regime and allied fighters near oil and gas installations in eastern Syria.
Moscow said five Russians were likely among the victims, blaming the incident on a “lack of co-ordination” by the pro-Assad group with Russian command.
But today, de-confliction channels in place since 2015 to prevent any clash between the Russians and the Americans seem to be bearing their fruit.
But long term, both sides have very different goals.
