Poland’s government has authorised the construction of a new barrier along the 210-kilometre border with the Russian exclave of Kaliningrad.
Polish Defense Minister Mariusz Blaszczak said on Wednesday the frontier needs to be "sealed" so that the country feels secure.
The move comes amid suspicions that Moscow plans to facilitate illegal border crossings by Asian and African migrants.
Blaszczak said the decision came after Russia's aviation authority recently launched flights from the Middle East and North Africa to Kaliningrad.
Preparatory work on the new, temporary barrier has begun, involving Polish soldiers specialised in demining.
Blaszczak said the barrier would be made of three rows of razor wire -- 2.5 metres high and 3 metres wide -- with an electronic monitoring system and cameras. On the Polish side, a fence will keep animals away.
The barrier is due to be completed by the end of 2023.
Poland erected a steel wall along its border with Belarus after thousands of migrants attempted to cross last year.
The European Union has accused Minsk -- a key ally of Moscow -- of facilitating illegal migration in a "hybrid" attack to destabilise the bloc.