Image: Mikhail Japaridze / AOP

President Sauli Niinistö signed stricter security policies into law Monday, making it illegal for unidentified military groups to cross the border and conduct activities in Finland as of today, Saturday.

The move is meant to tighten Finland's territorial integrity against a situation like that seen in Ukraine in 2014, when what Ukrainians coined "little green men" who claimed they were local militia led an insurgency. The separatists seized government buildings and police stations, and held unrecognised status referendums. At least some of the unmarked men were largely understood to be from the Russian Army, although Moscow denied it.

The new Finnish law defines unidentified militia as an organised military group that is kitted out or armed, supported or encouraged by a foreign power and whose country of origin cannot be ascertained. It bans such groups outright from entering or residing in the country, making any violations punishable as a criminal act in the Criminal Code.

The Ministry of Defence says the amendment is intended to protect Finland's domestic security and safeguard its territorial sovereignty and integrity. It says the change is necessary to meet the changed security situation and new kinds of threats.