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More than 95,000 troops belonging to Russia and its regional allies have started the annual Center exercises that span from the Volga to Siberia.

"Center-2015 is the final step in the armed forces' military preparations during 2015," said a statement from the ministry of defense, which said that it conducted nearly 80 military drills in August alone, as well as an unannounced inspection of the troops involved in the exercises last week.

The war games will engage more than 7,000 pieces of armor, up to 170 planes and 20 warships. 20 different training ranges will be used as troops belonging to all security branches, including border guards, FSB and drug police, will make maneuvers ranging up to 6,000 km. The exercises are scheduled to finish on September 20.

"What we are seeing now has not been seen since the Cold War - late 1970s and early 1980s. The army isn't just testing out new vehicles, equipment and techniques, but is using ever greater resources for doing so," military historian Vyacheslav Filatov told Russia's army-sponsored Zvezda channel.

Kazakhstan will provide troops while other members of the Collective Security Treaty Organization (CSTO), which also include Belarus, Armenia, Tajikistan and Kyrgyzstan, is sending officers to observe and take charge of segments of the drill.

The scenario for the war games sees the allied army attempting to localize an international threat coming from central Asia. Most troops will be purposefully operating in unfamiliar terrain, and there will be simulations of the need to treat a huge numbers of casualties, with "wounded" troops being delivered to mobile hospitals.

"While these maneuvers are defensive in nature, NATO will be looking on with concern," military expert Sergey Fedorov told Zvezda. "They are astonished by the scale of the war games - it is something they have rarely seen, and would never practice themselves, restricting themselves only to limited situational drills."

Also starting Monday, about 1,000 troops from Latvia, with the same number being supplied by NATO allies, including US, UK and Germany, begun conventional training exercises in the country. A day earlier the alliance finished Swift Response 15, the biggest military exercises in Europe since the collapse of the Berlin Wall, involving about 5,000 soldiers.

Earlier in the month, the US deployed two MQ-1 Predator long-range unmanned surveillance drones and 70 airmen to Latvia on a training mission.

In May, Lithuania, Latvia and Estonia jointly asked for permanent NATO bases, alleging that Russia has the capacity to invade them within four hours of ordering an attack. Moscow lashed out at the move, saying it contravenes the 1997 NATO-Russia Founding Act.