"Forty-five people with varying diplomatic status have been ordered to leave Poland," foreign ministry spokesman Łukasz Jasina told reporters.
"Russia is our neighbour, and it will not disappear from the map of Europe, but its aggression against Ukraine shows that it is an unfriendly state, and even one that is hostile to Poland," he added.
The announcement came after Polish Interior Minister Mariusz Kamiński tweeted earlier in the day that Poland would expel "45 Russian spies posing as diplomats."
Poland on Wednesday announced it had detained a man on suspicion of spying for Russia.
Source: IAR, PAP, Reuters