Russia's defence minister has announced new military exercises in Russia's south and west in reaction to the mounting unrest in eastern Ukraine.

Ukrainian troops on Thursday moved against pro-Russia militants in eastern Ukraine, killing at least two in clashes at checkpoints.

Russian Defence Minister Sergei Shoigu said in comments carried by the Russian news agencies that Russia has launched new military exercises involving ground troops in the south and the west and the air forces that will be patrolling the border.

He quoted tensions in Ukraine and NATO exercises in Poland as the reasons for the move.