A Russian warship fires during celebrations to mark Navy Day in the Crimean port of Sevastopol July 27, 2014. Reuters Russia's plan to add 80 new warships to its Black Sea fleet will put the country's navy even further ahead of the US Navy in terms of sheers numbers.

Both countries had been on nearly equal footing with nearly 300 warships before Russia moved ahead of the US with the seizure of 51 Ukrainian vessels after invading the Crimean peninsula in March, Kyiv Post reported.

The new ones, planned for use by 2020 at a second Russian base on the Black Sea, would put the Black Sea fleet alone at 206 vessels, according to Vice Admiral Alexander Vitko.

The expansion is best understood as both a cause and a part of the growing tension between NATO and Russia as a result of its annexation of Crimea and its sponsoring of the Assad regime in Syria. There, too, its navy's reach is at stake: Syria hosts Russia's only port in the Mediterranean, where Russian ships can refuel without making the long trip through the straits that traditionally divide Europe and Asia.

But depending on how you measure size, the US is likely to hold on to its naval supremacy.

"As much as the US Navy has shrunk since the end of the Cold War, in terms of tonnage, its battle fleet, by one estimate, is still larger than the next 13 navies combined — and 11 of those 13 navies are U.S. allies or partners," then Secretary of Defense Robert Gates told an audience at the Naval War College in Rhode Island in 2009. "In terms of capabilities, the over-match is even greater."

Gates went on to say that the US will maintain its 11 active aircraft carriers through 2040 at least, much more than any other country owns.

The Mistral-class helicopter carrier Vladivostok is seen at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, September 4, 2014. Stephan Mahe/Reuters Naval assets have often served as currency in diplomatic statements. After hesitating for weeks, France finally pulled the plug on the sale and delivery of warships to Russia, part of a criticized $1.7 billion arms deal that had been agreed to before Russia's aggressive move in Crimea.

And earlier this week, Chinese ships docked at Iran's main port for "a friendly visit," China's state-owned news agency Xinhua reported. The New York Times reported that Iranian navy members announced joint drills in safety at sea and combatting piracy, though the unprecedented visit also signals close ties between the two governments: China is Iran's biggest buyer of oil.