"The Russian air force has increased the intensity of its strikes against targets of the armed units of international terrorist organisations near the city of Palmyra," the ministry said in a statement today on its Facebook page.
"Since July 12, Russian air force planes have conducted more than 50 strikes against Islamic State personnel and material in this area."
Six Tupolev bombers flew out of an airbase in Russia this morning and conducted strikes east of Palmyra, near the cities of Arak and Sukhna, as well as in the Homs region, the statement said.
IS fighters were forced out of Palmyra by Syrian regime forces in March with Russian backing, but Arak and Sukhna remain out of the government's control.
Arak, located 35 kilometres east of Palmyra, is a small town that has strategic importance because of a nearby oil field, while Sukhna, 70 km northeast of Palmyra, is an IS bastion.
Russia is stepping up its bombing campaign in Syria as US Secretary of State John Kerry is set to meet President Vladimir Putin in Moscow today in Washington's latest bid to revive the stalled Syrian peace process.
Russia and the US appear increasingly at odds over the way forward amid heightened diplomatic tensions.
