Biggest military exercise since the Soviet era carried out across Siberia and the Russian Far East

President Vladimir Putin personally monitored the surprise inspection of combat readiness of troops during a trip to Sakhalin Island in the Russian Far East. 

Such exercises 'are very useful and effective from the point of view of revealing problems and their elimination', he told Defence Minister Sergei Shoigu.

'The activities for the snap inspection of combat readiness are proceeding in an orderly way and strictly according to plan', said a Defence Ministry spokesman.

'No actions that would violate international obligations have been allowed,' said deputy defence minister Anatoly Antonov.

Russian and foreign observers see the exercises, the largest since the end of the Soviet Union, as a sign of Russia strongly asserting its national interest in Siberia and eastern Russia. Foreign military attaches were informed in advance of the exercises which are due to end on 20 July. 

Retired military officer Konstantin Sivkov told Nezavisimaya Gazeta that the Sakhalin part of the manoeuvres was intended to simulate a response to a hypothetical attack by Japanese and US forces.

Meanwhile, a Moscow military analyst, Alexander Khramchikhin, said: 'It's quite obvious that the land part of the exercise is directed at China' - discouraging Bejing from future expansionist plans. He claimed 'the sea and island part of it is aimed at Japan'.

However, other military exercises have taken place elsewhere on Russian territory. 

'The main purpose of the activities is to check the readiness of the military units to perform assigned tasks and evaluate of the level of personnel's training and technical preparation as well as the level of equipment of units with arms and military equipment,' said the Defence Ministry. 

Jets from the Japanese and South Korean air forces accompanied two Russian Tu-95 fighter jets during a seven hour flight as part of the exercises.