A US-backed alliance of Syrian Kurdish and Arab fighters has begun a campaign to expel Islamic State (IS) militants from land north of Raqqa.
The Syrian Democratic Forces (SDF) is believed to have deployed about 30,000 fighters.
US-led coalition warplanes will support the offensive and Russia has also given its backing.
The SDF did not mention any plan to take Raqqa, the de facto capital of the "caliphate" proclaimed by IS in 2014.
The alliance, which is dominated by the Kurdish Popular Protection Units (YPG) militia, has emerged as a key ally of the US-led coalition over the past two years, leading the fight against IS on the ground in northern Syria.
With the help of US airpower, it has taken control of about 26,000 sq km (10,000 sq miles) of territory, including a 400km (250 mile) stretch along the Turkish border.