Rebels seized a town in southern Syria from groups loyal to the Islamic State group just a day after fighters captured another town from the hard-line militants in a separate insurgent assault in the north, a rebel source and a monitoring group said.

The rebels had by late Friday taken control of Tasil in Deraa province, which is near the Jordanian border and the Israeli-occupied Golan Heights, the source and the British-based Syrian Observatory for Human Rights said.

They drove out fighters from the Yarmouk Martyrs' Brigade and the Muthanna Movement, which they said were groups loyal to the terrorist organization, aka ISIS.

"Our battle continues against them until we have cleansed the area of them," said Abu Ghiath al-Shami, a spokesman for the Alwiyat Seif al-Sham group, which is part of a rebel alliance in the south.

He described the latest attacks against the jihadists as a "widened campaign against Daesh," using an Arabic acronym for ISIS.

It was the second blow dealt by insurgents fighting against ISIS and affiliated fighters in as many days.

In a separate assault in the north of the country near the Turkish border Thursday, rebel forces took over a town that had been the main ISIS stronghold in the northern Aleppo countryside.

A cessation-of-hostilities agreement in Syria that began Feb. 27 has slowed fighting in some areas in western Syria but has not halted the violence. ISIS and the al Qaeda-linked Nusra Front are not included in the truce.

The Syrian army and its allies, backed by Russian air power, are separately fighting ISIS.

Clashes between the government and non-jihadist rebels have continued in some areas during the ceasefire.