Video posted on Russian social media showed military trucks carrying Iskander ballistic missiles – which can carry nuclear warheads – moving through the country, reportedly on a highway to Vyborg, near the Finnish border.
The apparent deployment came just a day after Finland and Sweden each announced formal plans to apply for membership of Nato.
Russia’s foreign ministry warned yesterday that the move was a ‘grave mistake’ and would have ‘far-reaching consequences’.
Vyborg is located just 30 miles from Finland and 135 miles from Helsinki, putting it well within missile range.
The Iskander is a short-range ballistic missile developed by Russia that went into service in 2006 to replace the Soviet-era Scud and Tochka rockets.
Iskanders are the workhorse of Russia’s missile forces and can perform a wide variety of roles depending on the warhead they are fitted with.
Warheads include thermobaric, cluster, armour piercing, bunker-busters, and electromagnetic for taking out radar systems.
But the most eye-catching of the Iskander’s warheads is a nuclear charge, thought to be around four times as powerful as the bomb that destroyed Hiroshima.
The missiles have a range of up to 300 miles and are most-commonly carried by road-mobile launch vehicles, which makes the missiles much harder to find and destroy.
The new deployment to the Finnish border also comes as Nato began staging a huge drill in Estonia to rehearse its response to an attack from Russia.
Some 15,000 troops from 10 different countries – including Finland, Sweden and a small detachment from Ukraine – will participate in the exercise dubbed ‘Siil’ or ‘Hedgehog’ which will take place just 40 miles from the nearest Russian base.