The week-long exercise dubbed "Vostok-2018" also includes the Mongolian army.
The exercises are taking place at a time of heightened tensions between the West and Russia, including accusations of Russian influence in Western affairs and the ongoing conflicts in Ukraine and Syria.
Considering Russia's recent behaviour, Europe and the U.S. could be forced into a position where war becomes inevitable, he said.
Zapad-81 Soviet war games were the largest exercises ever held back in 1981, with about 100,000 to 150,00 troops participating.
The military arranged several artillery batteries stocked with mid to long-range S-300, S-400, Tor and Buk missiles, the likes of which Moscow has recently sold to Syria and Iran despite protests from the United States and Israel.
The Vostok 2018 exercise will last until September 17.
North Atlantic Treaty Organisation and European governments are eyeing the exercises closely, watching to see what they reveal about military co-operation between Russian Federation and China, and their mounting military might.More news: After Florence, sea level rise threat will remain for North Carolina shore
She added: "China has growing military capabilities and is playing an increasingly significant global role. I see little in the long-term that aligns Russian Federation and China", Mattis told reporters in Washington.
In 2017, Russian Federation conducted series of military drills in its western regions, in collaboration with Belarus.
A subsequent report from the Mint Press News further revealed that the drill will see huge action consisting of 300,000 troops, close to 40,000 military vehicles, a thousand aircraft, a couple of Russian naval fleets, and the entire airborne units coming from China.
It is noted that the exercises will be held under the leadership of defense Minister Shoigu Serge from 11 to 17 September in the far East of Russian Federation and in the neighboring waters of the Pacific ocean.
Putin is preparing his military for "warfare on a huge scale" to satisfy "delusions" that Russian Federation can defeat Western nations in a global conflict, according to an expert on his armed forces.
Putin, who is armed forces commander-in-chief, is expected to observe the exercises this week alongside Defence Minister Sergei Shoigu, who is overseeing them.
Russian Federation has said it is showcasing methods developed during its military intervention in Syria, giving Chinese forces - which haven't fought in a war since 1979 - a glimpse of real combat skills.