Interfax cited Russia’s Western Military District as saying on Monday about 1,000 troops took part in the operation.
Russia has amassed tens of thousands of troops at staging posts close to Ukraine and demanded that its southern neighbour not be admitted to NATO and that no offensive weapons be deployed there or in other neighbouring countries.
Some troops have started returning to permanent bases after drills near Ukraine.
Russia’s deployment of tens of thousands of troops to the north, east and south of Ukraine had fuelled fears in Kyiv and Western capitals that Moscow was planning an attack.
Russia denies any such plans, stressing it needs pledges from the West – including a promise from NATO not to expand the alliance eastward towards Russian borders – because its own security is threatened by Ukraine’s growing ties with the Western alliance.