Polish authorities have detained a Russian citizen and banned four others from entering Poland for five years on allegations of "information warfare."

Authorities say they tried to fuel animosity between Poles and Ukrainians and sought to challenge Polish views on history with a Russian narrative.

The move comes amid rising fears that Russia is seeking to destabilize Poland and exacerbate Polish-Ukrainian tensions that would leave Ukraine isolated. Russia invaded Ukraine and annexed the Crimean Peninsula in 2014.

Poland's Internal Security Agency, which investigates espionage and terrorism, said Thursday that it had detained a Russian woman identified only as Yekaterina C. and would expel her.

The agency accused the Russians of being engaged in "hybrid" activities, a term used to describe non-military but subversive tactics that Russia is suspected of using to further its interests.