Russian President Vladimir Putin said Russian warships had fired cruise missiles on Islamic State group positions in Syria for the first time.
The ground operation aims primarily at targeting the jihadi groups in the northern countryside of Hama.
The Hamah battle marks the first instance where the Syrian military ground force carry out a broad offensive under the direct Russian air support.
Russia started launching airstrikes against IS positions in Syria last week, at the request of Syrian President Bashar Assad.
The Russian Defense Ministry on Monday confirmed that it will continue to carry out airstrikes against militant targets in Syria.
NATO has called on Russia to immediately end air strikes “on the Syrian opposition and civilians”.
Turkey, a NATO member with the alliance’s second biggest army, has summoned the Russian ambassador for an explanation. It’s also warned Moscow against future incursions.