Amid rising tensions between NATO and Russia, the two sides are building up forces in several key places, including the Black Sea.

Crimea, which Russia seized from Ukraine two years ago, is on the Black Sea, and that's also where Russia recently stationed a new frigate, the Admiral Grigorovich, inviting journalists on board at the Russian base in Sevastopol.

The Russians insist this is not part of a build up directed at NATO, yet both sides have been making moves that make the other wary.

In Sevastopol, we took a launch down the channel to where the warship was tied up. The Admiral Grigorovich is a sleek, 400-foot vessel that cruises at around 35 miles per hour. Many of its armaments are hidden behind the ship's streamlined exterior.

Capt. Anatoly Velichko says the ship's main warfare mission is to fight other ships at sea, and to destroy any coastal installations an enemy might have. Since the vessel is highly automated and has all the latest weaponry, it requires a relatively small crew of about 200.

Velichko showed off the vessel's torpedo tubes and the launcher for its guided missiles. In terms of weapons, he says, it's the equal to any ship of its size in the world.

But not everyone agrees that the new Russian ship is state-of-the-art.

Eric Wertheim, an expert on combat ships at the U.S. Naval Institute, says the Admiral Grigorovich represents a significant improvement for the Black Sea Fleet.

But, he adds, "the change is not necessarily that they are incredibly capable warships now, although they are modern and better than what was there before, but just the simple fact that compared to what was there before was really in bad condition and decades old."

Wertheim says all the countries in the region, including the NATO members, need to be aware that Russia has new capabilities that will play an important role in the Black Sea.

Russia-NATO Tensions

It's part of a larger strategic game playing out between NATO and Russia.

One side of the Black Sea is lined with NATO countries — Turkey, Bulgaria and Romania. Those countries and the United States are taking part in a Black Sea naval exercise this month, along with vessels from Ukraine and Georgia.

And during a recent summit meeting in Warsaw, Poland, NATO announced plans to deploy a battalion of troops in each of four countries: Estonia, Latvia, Lithuania and Poland.

The total will be about 4,000 troops, a token number against the tens of thousands of troops that Russia can muster on its borders, but Russia bristled at the plan.

Russian President Vladimir Putin accused NATO of increasing "its aggressive rhetoric and aggressive actions near our borders. In this environment, we must pay special attention to strengthening our country's defense capabilities."

Naval Ties To Sevastopol

The Russian Black Sea Fleet has been based in Sevastopol since 1783, when the naval force was created under Empress Catherine the Great.

The governor of the city, Sergei Menyailo, is a former commander of the fleet, and he's deeply suspicious of any NATO presence in the region.

Menyailo acknowledges that Russia has been adding to its Black Sea naval force, but he says the buildup is not part of an arms race.

"Aren't they getting new ships in neighboring countries, in the U.S. and in Turkey?" he asks. "Why don't you call that an arms race? Wait, so you can do this but we cannot?"

Meanwhile, back on the frigate, the Russian sailors say they're ready for whatever comes their way.

I asked 25-year-old Anton Kruglov if he had any message for his American counterparts.

"Seven feet under the keel to all sailors," he said, meaning "may you always have deep water and safe sailing."

I asked if he expected to meet American sailors in the Black Sea.

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