Syrian regime troops advanced overnight against the "Islamic State of Iraq and Syria" (ISIS) in the country's north and centre, drawing closer to the key battleground of Deir Ezzor, AFP reported Sunday (August 6th).

The Syrian Observatory for Human Rights said the regime had made "significant progress" south of al-Raqa city.

"There is now just four kilometres between regime forces and the town of Madan, which is the last town controlled by ISIS in the al-Raqa countryside," the Observatory said.

Madan lies next to the border between al-Raqa province and Deir Ezzor, an eastern province mostly held by ISIS.

Extremists have besieged regime forces and civilians inside the provincial capital since 2015.

The Syrian regime and its allies are battling ISIS in the south of al-Raqa province separately from an offensive by the Syrian Democratic Forces (SDF), an Arab-Kurd alliance fighting inside al-Raqa city.

The regime also is fighting ISIS in central Homs province, where overnight they captured the last town the group holds in the area, the Observatory said.

The capture of al-Sukhna opens the route for the regime to advance towards Deir Ezzor on a second axis.

There was no official confirmation of al-Sukhna’s capture from Syria's government.

The Observatory said at least 64 ISIS fighters were killed in clashes with the regime and airstrikes across the Badiya region on Saturday. Among the dead were 30 killed in the fight for al-Sukhna.