Polish authorities claim to have dismantled an espionage group, which is alleged to have been working for Russian intelligence.
According to Warsaw, the suspected spies had placed hidden cameras on important railway routes, mainly in the southern Podkarpackie region, and near the key airport used by US arms deliveries and President Biden on his way to visit Kiev.
Officials say nine suspects have been arrested. An earlier report on the polish media, which had the number at six, included a claim that the suspects were foreign nationals.