Shoigu said that about 300,000 military personnel would take part, twice as many as the largest war games conducted by the Soviet Union: the Zapad-81 exercises in 1981.
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. According to reports, Chinese soldiers are also taking part in the war exercise for the first time.
Collin Koh, a research fellow at the S Rajaratnam School of International Studies at Nanyang Technological University in Singapore, said the shift away from anti-terrorism drills to more conventional war games could pave the way for greater cooperation between China and Russian Federation.
President Vladimir Putin is expected to attend the war games after hosting an economic forum in Vladivostok where Chinese leader Xi Jinping is one of the guests.
Xi, whose country is locked in a tense confrontation with the United States over trade and tariffs, said that Russian Federation and China should work together to oppose protectionism and what he called unilateral approaches to worldwide problems.
"The focus of the drill has expanded from anti-terrorism to allied defense and counterattack", a China defense ministry statement said.
Given the close proximity, the invitation of the Chinese and Mongolian militaries to take part is likely to be a diplomatic as much as a strategic move on the part of the Russians, given the fact that the massive scale of the exercises would have been seen as a threat had they not been involved.
"With its Vostok-2018 exercise, Russia sends a message that it regards the United States as a potential enemy and China as a potential ally", wrote Dmitri Trenin, a former Russian army colonel and director of the Carnegie Moscow Center think tank.
Joint military drills are not uncommon but are rarely seen on such a large scale.
Song Zhongping, a Hong Kong-based military commentator, said Beijing, which regards the defence of its sovereignty over most of the South China Sea and the self-ruled island of Taiwan as core interests, needed to strengthen its capabilities in preparation for possible real-life military conflicts.
Russia´s previous military exercise in the region, Vostok-2014, was nearly half the size, with 155,000 soldiers participating.
"Fundamentally, the goal of this specific exercise is to project Russian military power in the Asia-Pacific region", Kokcharov said.
Russian Federation on Tuesday launched its largest military exercise at the Tsugol training range in Russia's Trans-Baikal region in eastern Siberia.
"These are very important drills and they are part of routine annual work to develop the armed forces", Dimitry Peskov, Putin's spokesman, told reporters Tuesday.
The war games are held a year after Russian Federation staged major drills in the country's west last September, unnerving neighbouring former Soviet republics.
The Kremlin has poured scorn on complaints Vostok-2018 is a cause for concern among North Atlantic Treaty Organisation members and Western nations more broadly.
"[It also] signifies that the political strategic trust and military cooperation between China and Russian Federation has reached a historic high".
He added: "Russia also thinks that the worldwide reactions to its appalling behaviour over recent years - including the seizure of Crimea, aggression against Ukraine, causing and abetting untold suffering in Syria, the attempted murder of the Skripals and more - are just more indications of this "aggressive and unfriendly" attitude by the rest of the world".