Air strikes thought to have been conducted by a US-led coalition Thursday killed 14 civilians, including six children, in a northern Syrian village held by the Islamic State group, a monitor said.
"The raids hit the village of Al-Matab after midnight and were likely carried out by the coalition," said Rami Abdel Rahman of the Syrian Observatory for Human Rights.
Al-Matab lies near a key road linking Raqa -- IS's de facto capital -- to Deir Ezzor city, the capital of the adjacent oil-rich province.
On Monday, fighters from the US-backed Syrian Democratic Forces cut off that route in a bid to encircle the jihadists in Raqa.
The US-led coalition has been backing the SDF's drive for Raqa with air power and hundreds of special operations forces as advisers.
Abdel Rahman said SDF fighters advancing on IS jihadists in Al-Matab, which lies about 55 kilometres (35 miles) southeast of Raqa.
The SDF, an alliance of Kurdish and Arab fighters, launched its offensive for Raqa in early November and has since seized swathes of territory in northern Syria.
But it is despised by Ankara, who condemns the group's dominant component -- the Kurdish People's Protection Units (YPG) -- as "terrorists" because of its links to an outlawed Kurdish militia in Turkey.