MOSCOW: Russia on Tuesday will launch the biggest military drills in its history involving 300,000 troops as well as Chinese soldiers, in a move NATO denounced as "exercising large-scale conflict".

The week-long deployment alongside Chinese and Mongolian armies dubbed "Vostok-2018" (East-2018) will start in eastern Siberia on September 11.

It comes at a time of escalating tensions between Moscow and the West over accusations of Russian interference in western affairs and the ongoing conflicts in Ukraine and Syria.

The Russian army has compared the show of force to the USSR's 1981 war games that saw between 100,000 and 150,000 Warsaw Pact soldiers take part in "Zapad-81" (West-81) -- the largest military exercises of the Soviet era.

But defence minister Sergei Shoigu said this time would be even larger, with 300,000 soldiers, 36,000 military vehicles, 1,000 planes and 80 warships taking part in the drills.

"Imagine 36,000 military vehicles moving at the same time: tanks, armoured personnel carriers, infantry fighting vehicles -- and all of this, of course, in conditions as close to a combat situation as possible," Shoigu said.

The Russian army will roll out all of its latest additions for the event: Iskander missiles that can carry nuclear warheads, T-80 and T-90 tanks and its recent Su-34 and Su-35 fighter planes.

At sea, the Russian fleet will deploy several frigates equipped with Kalibr missiles that have been used in Syria.

Russia's previous military exercise in the region, Vostok-2014, was almost half the size, with 155,000 soldiers participating.

The country's war games in Eastern Europe last year, Zapad-2017, saw 12,700 troops take part according to Moscow. Ukraine and the Baltic states said the true number was far bigger.

President Vladimir Putin is expected to attend Vostok-2018 after hosting an economic forum in Russia's far eastern city Vladivostok where his Chinese counterpart Xi Jinping is one of the star guests.

Russian military analyst Pavel Felgenhauer said the games were a "preparation for a future world war".

"The army's General Staff believes this will take place after 2020 in the form of either a global war or a series of conflicts with magnitude," he said.

"The enemy is the United States and its allies."

According to Felgenhauer, China's participation -- although modest with only 3,200 men -- will be a key factor at the drills.

"It's not just about a sign or a message, but about a preparation for a real-life war of great magnitude," he said.

This opinion was shared by NATO, which said that Vostok-2018 "demonstrates Russia's focus on exercising large-scale conflict".

"It fits into a pattern we have seen over some time -- a more assertive Russia, significantly increasing its defence budget and its military presence," said the alliance's spokesman Dylan White.

Russia has denied the drills are a cause for worry.

"Vostok-2018 is far from NATO's area of responsibility and does not affect the security of its member states," the Russian foreign ministry's spokeswoman Maria Zakharova said.

Relations between Russia and the West declined sharply in 2014 with Moscow's annexation of Crimea and the subsequent conflict in eastern Ukraine.

Since then Moscow has increased the number of its large-scale military exercises in the Caucasus, the Baltic and the Arctic. At the same time the Kremlin has accused NATO of expanding westwards and threatening Russian national security.

This week, Russia held military exercises in the Mediterranean.

More than 25 warships and around 30 planes took part in the drills, as Russia increased its military presence in Syria where it intervened to help the Bashar al-Assad regime in 2015.

Around 2,200 Ukrainian, American and other NATO soldiers took part in military exercises in western Ukraine in early September.

Last month, the Kremlin's spokesman said Russia's "ability to defend itself in the current international situation which is often aggressive and unfriendly to our country is justified, essential and without alternative".