Russia has begun its biggest war games since the fall of the Soviet Union close to its border with China, mobilising 300,000 troops in a show of force that will include joint exercises with the Chinese army.
China and Russia have staged joint drills before but not on such a large scale, and the Vostok-2018 (East-2018) exercise signals closer military ties as well as sending an unspoken reminder to Beijing that Moscow is able and ready to defend its sparsely populated far east.
Vostok-2018 is taking place at a time of heightened tension between the West and Russia, and NATO has said it will monitor the exercise closely, as will the United States which has a strong military presence in the Asia-Pacific region.
Russia's Ministry of Defence broadcast images on Tuesday of military trucks being transported on trains, columns of tanks, armoured vehicles and warships on the move, and combat helicopters and fighter aircraft taking off.
This activity was part of the first stage of the exercise, which runs until September 17, the ministry said in a statement. It involved deploying additional forces to Russia's far east and a naval build-up involving its Northern and Pacific fleets.
The main aim was to check the military's readiness to move troops large distances, to test how closely infantry and naval forces co-operated, and to perfect command and control procedures.
The location of the main training range for Vostok-2018 5000km east of Moscow, means it is likely to be watched closely by Japan, North and South Korea as well as by China and Mongolia, both of whose armies will take part in the manoeuvres later this week.
Ruissian President Valdimir 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.
Shoigu has said they are the biggest since a Soviet military exercise, Zapad-81 (West-81) in 1981.
Australian Associated Press