Syrian government forces on Saturday regained several villages from rebels in Hama, reversing the opposition's recent advances in the key central province, a monitoring group reported.
The regime's latest gains followed a massive counter-attack including artillery shelling and airstrikes against rebels in the north-eastern parts of Hama, the Syrian Observatory for Human Rights added.
No casualties were reported.
The advance is the first of its kind by the regime in the area since the opposition seized large chunks there in late August, the Britain-based watchdog said.
The regime forces took advantage of ongoing fighting between two rival powerful rebel groups in order to push against the opposition in Hama, added the Observatory, which uses a network of activists inside Syria.
Hardline Islamist force Ahrar al-Sham has been battling al-Qaeda-linked Jund al-Aqsa since Thursday on the outskirts of Hama and the north-western Idlib province.
Ahrar al-Sham is thought to be the largest rebel force in northern Syria.
Jund al-Aqsa is spearheading a rebel campaign that has driven back government forces north of Hama in recent weeks.