The Russian military says it’s building a helicopter base just 35km off the Finnish coast.
The new facility is close to Kotka, on an island in the Baltic Sea.
Russian forces are constructing five helipads, a command and control centre, weather station, fuel depot and maintenance facilities on the island of Gogland, which is known as Suursaari in Finnish.
Special lighting being installed could help with year-round, all-weather military operations.
The construction was started in a training exercise the Russians are describing as “special tactical drills”.
According to the Russian Tass news agency, the new base will be able to handle all the different types of transport and combat helicopters used by the western military command.
Army aviation crews have already been practicing landings and take-offs from the new facility, according to the military.
Gogland used to belong to Finland but was ceded to the Russians after the war. Russia claims it’s an important location for the defence of St Petersburg, even though it lies well to the west of the natural land border of both Finland and Estonia, and Russia.
The last military battle to be fought on Gogland was back in 1944, when the Finnish garrison stopped a German attempt to capture the island.