Russia's air strikes hit northern parts of Hama province and nearby areas in Idlib province, targeting towns close to the main north-south highway that runs through major cities in western Syria, the Syrian Observatory for Human Rights said.
Ground attacks using heavy surface-to-surface missile bombardments targeted at least four insurgent positions in the area and there were heavy clashes on the ground, the head of the Observatory Rami Abdulrahman said.
"There is no information yet of any (government) advances on the ground, but the air strikes have hit vehicles and insurgent bases," Abdulrahman added.
It was reported last week that allies of Syrian President Bashar al-Assad, including Iranians, were preparing a ground attack in Syria.
Abdulrahman, who tracks the conflict using sources in Syria, said the ground assault was being carried out by 'regime forces' and their allies, with no immediate sign of Russian involvement on the ground.
Russia, a top ally of Assad, started air strikes in Syria a week ago, saying they were targeting hardline Islamic State militants.
But fighters on the ground and Western countries have said the Russian campaign is mainly focusing on other rebel groups that have seized government held areas in the west in recent months, and is aimed at shoring up Assad rather than combating hardliners.
Russia's strikes today targeted the towns of Kafr Zita, Kafr Nabudah, al-Sayyad and the village of al-Latamneh in Hama province and the towns of Khan Shaykhun and Alhbit in Idlib, the Observatory said.

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