Russia's defense ministry says the country will hold large-scale military drills in the Russian Far East from late August through early September.

The ministry announced on Tuesday that the quadrennial Vostok military exercises will be held in the Eastern Military District from August 30 to September 5.

The ministry mentioned 13 training grounds to be used for operations, including those on Etorofu and Kunashiri, two of the four islands Japan calls the Northern Territories.

Russia controls the four islands. Japan claims them. The Japanese government maintains the islands are an inherent part of Japan's territory. It says the islands were illegally occupied after World War Two.

China's army and air force took part in the Vostok exercises for the first time in 2018.

The ministry said foreign troops will take part in the coming drills, without mentioning specific countries by name.

Observers say Russia apparently intends the drills to send the message both within and outside the country that it has sufficient military manpower despite its prolonged invasion of Ukraine.