MOSCOW - Russia's air forces will intensify airstrikes against the posts of extremist group Islamic State (IS) in Syria, a senior military official said Saturday.

"We will not only continue conducting our airstrikes, but will also increase their intensity," Andrey Kartapolov, deputy chief of the General Staff of Russian Armed Forces told reporters.

The primary targets are IS command points, ammunition and explosives depots, communication hubs, workshops to produce weapons and militant training camps, he said.

Russia's aircraft have carried out more than 60 missions and destroyed over 50 IS facilities during the round-the-clock airstrikes, he said.

"Over the past 72 hours, we have managed to undermine the material and technical base of terrorists and significantly reduce their combat potential," Interfax news agency quoted Kartapolov as saying.

He added that reconnaissance units obtained information of terrorists leaving districts under their control.

Meanwhile, the official stressed that all relevant countries were informed of Russia's airstrikes in advance, and that the U.S.  confirmed to Russian side that there were only terrorists in the airstrike regions.

Moscow started the airstrikes which it said were targeting IS forces and fighting terrorism, but U.S. leaders are skeptical of that. (Xinhua)