KAJAANI - Finland is barely out of the treaty banning them but the country's armed forces are already training soldiers to lay anti-personnel mines, citing a threat from neighbouring Russia.
Trudging through snow, a young Finnish conscript carefully draws a thin blue wire between two pine trees. The other end is attached to a hidden mine some 20 metres (65 feet) away.
"We are in the process of figuring out what's the most effective way to use them," said Lieutenant Joona Ratto, who teaches military service conscripts how to use the devices that Finland had banned in 2012.
Stationed with the Kainuu Brigade, which is responsible for defending 700 of the 1,340-kilometre (833-mile) border Finland shares with Russia, Ratto and his colleagues are gearing up to train the 500 active-duty soldiers, 2,500 conscripts, and 5,000 reservists who pass through the garrison each year.
Dropping decades of military non-alignment, Finland applied to join NATO in the wake of Russia's 2022 invasion of Ukraine and became a member in 2023.
Like the nearby Baltic states and Poland, it also decided to withdraw from the Ottawa Convention, which prohibits the use, stockpiling, or production of anti-personnel mines.
No longer bound by the international treaty since January 10, Finland is now free to bury or conceal the small, inexpensive devices, which have been criticised for causing injuries to civilians long after conflicts end.
From a military perspective, antipersonnel mines are a necessary evil, according to Ratto.
"We can use them to either stop the enemy or maybe alarm our own troops in the defensive positions", giving troops time to prepare for "the firefight", he told AFP among the wintery landscape of pine and spruce trees.
While the war in Ukraine has cemented the role of drones, the trench war had demonstrated that, although old, "they are still effective and they have an important role on the battlefield", said Colonel Riku Mikkonen, inspector of engineering for the Finnish Army.
Nearby, other soldiers train on a road.
A warning sign has been put up reading "Miinoja, mines", depicting a skull in a downward-pointing red triangle -- the international symbol for a mined area.
A powerful drill is used to penetrate the frozen ground to bury training anti-tank mines, which were never banned.
Finnish conscripts install anti personnel mines on a tree in a snow-covered forest at the Kainuu Brigade in Kajaani, Finland.