The Syrian army crossed into Raqqa province on Tuesday, capturing two villages from Islamic State Group, the Syrian Observatory for Human Rights said, an advance coinciding with the start of a U.S.-backed assault on Raqqa city.
The Russian-backed Syrian army and allied militias advanced into Raqqa province from neighbouring Aleppo province where they have seized swathes of territory from Islamic State Group this year.
The villages seized - Khirbet Mohsen and Khirbet al-Saba - are about 80 km (50 miles) from Raqqa city and are located 7 km south of the main road linking Raqqa and Aleppo.
The U.S.-backed campaign to capture Raqqa is being fought by the Syrian Democratic Forces (SDF), an alliance that includes the Kurdish YPG militia.
In May, the Syrian government described the Kurdish war with Islamic State Group as "legitimate" and said the military priorities for Damascus were Islamic State Group-held Deir al-Zor and the Badia region at the border with Jordan and Iraq. That suggests it does not intend to challenge the U.S.-backed campaign at Raqqa city.