MOSCOW (Reuters) - Russia is taking measures to respond to what it calls threatening military action by NATO, including combat readiness checks and troop exercises, news agencies cited Defence Minister Sergei Shoigu as saying on Tuesday.

Shoigu was cited as saying that NATO was planning to deploy 40,000 troops and 15,000 military personnel close to Russian territory. A large unexplained build-up of Russian forces close to Ukraine's eastern border and in Crimea, which Moscow annexed from Ukraine in 2014, has escalated tensions in recent weeks.

Russia on Tuesday called the United States an adversary and told U.S. warships to stay well away from Crimea "for their own good", calling their deployment in the Black Sea a provocation designed to test Russian nerves.