The civil war in Syria has seen the Kurds, the country's long-oppressed minority, emerging as a powerful force, led by a leftist political party and its armed wing which have managed to get the support of the United States for the past two years.
The Democratic Union Party (PYD) and the militia, the People's Protection Units (YPG), have declared autonomous zones in northern Syria and recently announced a federal system of administration.
Syrian rebel factions and the Syrian government - bitter enemies - are both opposed to the Kurdish plans, fearing a division of the country's territory. The PYD, however, says federalism is the solution to Syria's civil war and sectarian violence.
Syrian Kurdish aspirations were long repressed under the Arab nationalist regime of President Bashar al-Assad and his father Hafez, who ruled Syria from 1970 until his death in 2000.
Syria's largest minority, the Kurds account for about 10 per cent of the country's pre-war population of 23 million. They live mainly in the north-east, as well as small areas along the northern border with Turkey. There are also large migrant populations in Aleppo.
Under al-Assad's Baath Party, the Kurds complained that they were denied many rights and that their culture and language was suppressed. Many Kurds were stateless, as the government did not grant them citizenship.
Kurdish areas in Syria saw only limited protests as the pro-democracy uprising against al-Assad started in March 2011.
In July 2012, al-Assad's forces suddenly withdrew from most Kurdish towns in the north and north-east, maintaining a limited presence only in the main north-eastern cities of Qamishli and al-Hassakeh. The PYD quickly took over.
There have been occasional clashes with government forces in recent months, in addition to fights with rebels, near frontline areas.
In September 2014, the Kurds were being pushed back. The Islamic State had recently declared itself a caliphate and was quickly gobbling up the Kurdish-held territory.
However, a US-led coalition decided to back the Kurds as a reliable, secular and cohesive ground force which was willing to fight Islamic State. Starting in Kobane, a symbolic town, the Kurds captured most of the Islamic State's territory along the border with Turkey.
The PYD is believed to be linked to the Kurdistan Workers' Party (PKK), which is fighting a decades-long guerrilla war against Turkey - also accused of supressing the minority group - and is banned by the European Union and United States as a terrorist organization.
Some Kurds in Syria belong to other parties and accuse the PYD of monopolizing power in Kurdish-held areas and repressing opposition. More conservative Kurds have even allied with Turkey and parties affiliated with Iraqi Kurdish leader Massoud Barzani.
The main Kurdish force in northern Syria says it has handed over control of Minbij city, west of the Euphrates River, to the local council.
Syrian Kurds condemn the Turkish incursion into Islamic State-held Jarablus, calling it a "declaration of war."
Syrian rebels supported by Turkey and US-backed Syrian Kurdish forces clashed Thursday in the north of the country, activists and Kurdish officials said, raising fears of a new confrontation over territory amid a Turkish led intervention.
Turkish Prime Minister Binali Yildirim said Saturday he believes Syrian President Bashar al-Assad is beginning to view as a "threat" Kurdish forces in the north who are backed by the United States and battling Islamic State.
The spokesman for the US-led anti-Islamic State coalition says the Syrian Democratic Forces, a group comprising several factions but dominated by the Syrian Kurds, have moved back across the Euphrates River, to the east.