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, Reuters has reported.
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.
Although Wednesday's combined assault marked a military escalation, it was not immediately clear whether there would be rapid gains in a conflict that has already dragged on more than four years.
"There is no information yet of any (government) advances on the ground, but the air strikes have hit vehicles and insurgent bases," Abdulrahman said.
A regional source familiar with the military situation in Syria said forces including Hezbollah fighters were taking part in the ground attack against four rebel-held areas.
