Russia launches a week of massive military exercises in the far east of the country this week and the Pentagon will be watching the "war games" very closely, experts told CNBC. As many as 300,000 Russian troops are expected to take part in large-scale military drills as part of "Vostok 2018," Russia's annual military training exercises taking place between September 11-17. Aside from personnel, up to 36,000 tanks, infantry fighting vehicles, armoured personnel carriers and other vehicles will be involved, Russia's Ministry of Defence said in a statement on their website on Tuesday. In addition, over 1,000 aircraft, helicopters and drones, and 80 ships and supply vessels will take part. Vostok 2018 will also see the Russian military practice massive airstrikes and measures against cruise missiles. This year's military exercises, widely known as "war games," are set to be the biggest to take place since 1981 when the Cold War overshadowed international relations.

Russia's T-90M battle tank at the Army 2018 International Military and Technical Forum, in Patriot Park. Sergei Bobylev | TASS | Getty Images

Russia is showing a diplomatic pivot to the east with China this year, with several thousands of its troops, participating in some of the military exercises taking place in the Siberian and the Far Eastern regions of Russia. Mongolia is also sending troops to be involved in the drills. The Pentagon will be watching Russia and China's expanding military capabilities, as well the upcoming "war games," very closely, according to a former U.S. national security official. "I'm not sure that the Pentagon is terribly surprised by this (military exercise)," Lincoln Bloomfield, Distinguished Fellow and Chairman Emeritus at the Stimson Center, a nonpartisan policy research center, told CNBC on Tuesday. "The Russians have been investing in some fairly sophisticated and troublesome systems, they're looking at the growing access to the Arctic and developing submarines, and I think the Pentagon is watching Russia very closely," he told CNBC's "Capital Connection". "Because (Russia has) an experienced military that understands expeditionary operations whereas China is a little bit new to that and the culture of China has not demonstrated itself to be overtly aggressive in a military way against important powers like the U.S. So, I think the Pentagon is watching very closely but they're looking at it (Russia and China's military cooperation) as a long, incremental process," Bloomfield, who served as a national security official in three previous administrations, noted.

Defensive, not offensive

Russia's defense ministry say the main objectives of the war games are to ensure Russia's military security and the preparedness of its troops and commanders. "The main objectives of the maneuvers are: to check readiness of command and control bodies when planning and regrouping troops, cooperation of ground forces and the Navy, improve skills of commanders and staff in command and control when preparing and conducting combat actions," Russia's defense ministry said. Still, the games come at a time of economic recovery rather than robust growth for Russia. Despite a recovery in the oil price which has been vital for the major oil-exporter, the country is still operating under economic sanctions following its annexation of Crimea in 2014.