Poland has refused to invite a Russian delegation to a ceremony to commemorate 80 years since the outbreak of World War II.
Krzysztof Szczerski, an aide to President Andrzej Duda, told the Polish news agency PAP on March 20 that Russia had not been invited to the events in September because of its actions in Ukraine.
Russia has been hit with numerous international sanctions for its annexation of Ukraine's Crimea in 2014 and ongoing support for separatists in eastern Ukraine.
Russia's Foreign Ministry said in a statement that it was "bewildered" by the snub.
"Despite the critical contribution of our country to defeating Hitler's Germany and liberating Poland from Nazi invaders, there is no place for Russia there," the statement said.
Russian President Vladimir Putin traveled to Poland in 2009 and delivered an address at a ceremony to mark 70 years since the start of the war, despite tensions at the time between Moscow and Warsaw.
On September 17, 1939, less than three weeks after Nazi Germany attacked Poland, triggering World War II, the Red Army also invaded the country, carving it up jointly with Germany.