MOSCOW, Oct. 13 (Xinhua) -- Less than eight percent of Syrian territory remains under control of the Islamic State (IS) as Syrian government troops supported by Russian jets have freed most of the country, Russian military said Friday.

IS-held territory declined by 5,841 square km in the past month and 142 settlements were liberated, Sergei Rudskoi, chief of the Main Operational Directorate of the Russian Armed Forces General Staff, said at a news briefing.

He said Syrian troops are successfully advancing in the east of the country, having repelled attacks by several thousand IS militants.

In central Syria, the government troops have completely eliminated IS units surrounded in the city of Akerbat, Rudskoi said.

The Syrian government troops and the Russian air force will continue operations against tge IS and other terrorist groups until their complete destruction, he said.

The ongoing Syrian civil war broke out in spring of 2011 between the government forces, along with its allies, and various forces opposing the government, including the IS militants.