A wave of Russian air strikes in western Syria on Wednesday was being accompanied by a ground assault on at least four rebel positions, a group monitoring the war said.
The ground attacks were being carried out by "regime forces" the Syrian Observatory for Human Rights said, a term it uses broadly to describe the Syrian military and allied local and foreign militia.
They also reported heavy surface-to-surface missile bombardments.
The attacks took place after an intense wave of air strikes in the Syrian province of Hama and nearby areas in the neighbouring province of Idlib.
No information about casualties has been released.
Yesterday, Russia conducted its first strikes against Isis held territory.
Russia has built up a "substantial" military presence including ground troops in Syria, according to the Nato secretary-general.
Jens Stoltenberg told journalists Vladimir Putin's forces have mainly been targeting opposition groups other than Isis.
“I will not go into any specific numbers but I can confirm that we have seen the substantial build-up of Russian forces in Syria - air force, air defences but also ground troops in connection with the air base they have," he said.
Mr Putin previously said he had no plans to deploy ground troops in Syria.
This article will be updated shortly
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