CONSTANTA NAVAL BASE, Romania — In the dimly lit war room of the Romanian frigate Regina Maria, glowing radar screens illuminate a cheat sheet for identifying Russian vessels.

The ship’s commander points to the newest warships, Grigorovich and Sviyazhsk, that have appeared on the horizon since Russia seized Crimea in 2014 and began to expand its Black Sea fleet. Romanian Cmdr. Alexandru Gobjila then points to older vessels, armed with the latest technology and weaponry, including supersonic Kalibr cruise missiles capable of reaching 1,600 miles into Europe.