Poland's defense minister on Thursday complained of "unprecedented" activity by Russia's navy and air force in the Baltic Sea region in recent days.
Tomasz Siemoniak said the majority of the incidents involved Russian operations in international waters, and that Sweden was the country most affected.
Siemoniak said Poland sees Russia's show of military strength primarily as an attempt to test NATO, adding that "it doesn't help to build good relations and trust."
He spoke in an interview with TVN24, which said that on Monday Dutch F-16s taking part in NATO's Baltic Air policing mission intercepted two Russian Su-34 bombers.
Siemoniak wouldn't give details of that incident, but said it is just "one of many."
He said the issue would be discussed later in the day in Latvia with counterparts from the three Baltic states.
Estonia's foreign ministry summoned Russia's ambassador on Wednesday after Estonia claimed a Russian plane had violated the country's air space. The Russian defense ministry denied it, saying the Russian military aircraft was making a routine flight from Moscow to the Russian Baltic Sea enclave of Kaliningrad "in accordance with international rules for the use of airspace."
On Sunday, NATO said Russian military activity "has been considerable" in recent months. It added, "Such activity can be destabilizing and potentially dangerous, if international norms are not respected."