Syrian government forces and their allies recaptured several towns and villages from rebels in the west of the country on Saturday, monitors and pro-Damascus media reported, reversing rare gains made by the insurgents in recent weeks.
The main government advances took place to the north of Hama, the British-based Syrian Observatory for Human Rights monitoring group said.
Damascus, backed by Russia's air force and Iranian, Lebanese and Iraqi fighters, holds the upper hand in Syria's key battleground of Aleppo, having encircled rebel-held areas of the northern city for all but a brief period since July.
Rebels in Hama province, further south, captured a series of government-held towns and villages after launching an attack at the end of August.
But government forces retook several of those on Saturday, in an attack which put them on the front foot in northern Hama for the first time in weeks, the Observatory said.
Lebanese Shi'ite group Hezbollah's Al Manar TV said the Syrian army had seized towns or villages including al-Talisiya, al-Qahira and Tel al-Usud. Hezbollah is fighting on the side of President Bashar al-Assad.
The Observatory said the government side had taken advantage of recent infighting between two insurgent groups in the countryside of Idlib, north of Hama's provincial boundary.
Those factions, the powerful Islamist Ahrar al-Sham and Jund al-Aqsa, which the United States says was once linked to al Qaeda, have been exchanging fire since early on Friday, the Observatory said.
In a separate government advance against insurgents near Damascus, the Syrian army and allied forces seized a large portion of the town of al-Hameh to the northwest of the Syrian capital, the Observatory reported.