North Atlantic Treaty Organisation said that Vostok-2018 "demonstrates Russia's focus on exercising large-scale conflict".
Tensions have been heightened between Russian Federation and the West in the wake of ongoing conflicts in Ukraine and Syria and the Novichok attack in Salisbury.
"It fits into a pattern we have seen over some time - a more assertive Russian Federation, significantly increasing its defense budget and its military presence", the alliance's spokesman Dylan White said last month.
The start of the exercises coincided with a bilateral meeting between President Vladimir Putin and his Chinese counterpart President Xi Jinping at a forum in Valdivostok, where they vowed to fight attacks on their economies.
"It fits into a pattern we have seen over some time - a more assertive Russian Federation, significantly increasing its defence budget and its military presence", said the alliance's spokesman Dylan White.
He said that an increasingly unpredictable geopolitical climate made partnership between Russian Federation and China particularly important.
China has sent about 3,200 troops, 900 combat vehicles and 30 aircraft to join the drills at a Siberian firing range - a significant deployment that reflects its shift toward a full-fledged military alliance with Russian Federation.
Mr Shoigu said Vostok-2018 will be "unprecedented in scale, both in terms of area of operations and numbers of military command structure, troops and forces involved", adding that it will also be "the largest preparatory action for the armed forces since Zapad-81".
Hong Kong-based commentator Song Zhongping said China is anxious to acquire more experience in large-scale operations that might become a factor in a conflict with the US and others over territorial claims in Asia. "If Russia had not invited China, that would have been viewed by Beijing as a potentially risky activity by Russia".
Peskov has earlier said Russia's "ability to defend itself in the current worldwide situation which is often aggressive and unfriendly to our country is justified, essential and without alternative".
Russian Federation will showcase some of its latest military hardware at Vostok-2018, including nuclear-capable Iskander missiles T-90 tanks and Su-35 fighter jets.
Russian Federation has faced ever harsher sanctions since angering the West and Kiev by annexing Crimea in 2014 and backing separatist rebels in eastern Ukraine.
"In some ways (Vostok-2018) will repeat aspects of Zapad-81, but in other ways the scale will be bigger", Shoigu said.
The Defence Ministry said in a statement Tuesday that the largest military drills since the end of the Cold War will involve about 36,000 tanks and 300,000 troops at sea and on the ground.
The Russian Ministry of Defense yesterday broadcast images of military trucks being transported on trains, columns of tanks, armored vehicles and warships on the move, and combat helicopters and fighter aircraft taking off.