Story highlights The Black Sea is becoming an increasingly contested space between Russia and NATO

American tanks and troops also took part in military drills in Zagan, Poland

(CNN) NATO members flexed their military muscle in Russia's backyard Monday, as allied warships headed toward the Black Sea while American tank fire echoed across Polish plains.

The naval force "Standing Maritime Group 2," which consists of eight vessels from eight NATO member states, is going to the Black Sea to participate in an exercise off the coast of Romania known as "Sea Shield."

The Black Sea, like the Baltics, is becoming an increasingly contested space between Russia and NATO as Moscow has militarized Crimea, according to the alliance.

"This is a demonstration of the alliance's resolve to defend all allies against any threat, and to enhance maritime security in the region," said a NATO official.

While "Sea Shield" is not technically a NATO exercise according to officials, it will include a number of NATO countries, including Bulgaria, Canada, Greece, Romania, Spain, the USA and Turkey.

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