The ship in question is of the "Tarantul"-class, missile-equipped corvettes dating from the 1970s and 1980s.
It is just the latest in a long series of surface and submarine ccraft to appear on the horizon, mirroring the flights of Russian air force planes in the skies.
Armed Forces on 27 APR in LV EEZ 5 nmi from territ. waters spotted RU Navy's Tarantul-class ship.— NBS (@Latvijas_armija) April 27, 2015
At the end of last week the NBS coast guard patrols also reported spotting a Russian navy Bereza-class vessel, which uses magnetic fields to shield other ships from being picked up as easily by enemy radar.
This week, lasting until Thursday, April 30 the Baltic states' are conducting joint minesweeping training operations Batron inside Lithuania's territorial waters and EEZ. The ships Virsaitis and Rūsiņš among the Latvian navy vessels taking part in the drills meant to test the minesweepers' readiness as part of NATO's Rapid Reaction Forces.
Altogether Russian military units have been seen by Latvia's borderzone territories in the air and on sea 39 times this year.
Armed Forces on 23 APR in LV EEZ 12 nmi from territ. waters spotted RU Navy's Bereza-class ship.— NBS (@Latvijas_armija) April 23, 2015
For those interested in how NATO coordinates its land-, air- and sea-based forces to patrol the Baltic region in light of Russia's increased military posturing there, watch the following video taken from inside an AWAC, where crewmembers demonstrate how aircraft radar have a wide-ranging view of the surface of the Baltic Sea as well as the airspace above it, so that any craft straying too close for comfort to the Baltic states' borders can be duly intercepted and monitored in a timely manner.