Poland is to summon the Russian ambassador over remarks which appeared to suggest he said Poland was partly to blame for the start of World War Two.
Sergey Andreyev said Poland had blocked a coalition against Nazi Germany several times in the run-up to war.
He also said the USSR's invasion of Poland in 1939 was not an aggression.
In an interview with a private Polish TV station aired on Friday evening, Mr Andreyev said that Poland had stood in the way of an alliance against the Nazis.
"Therefore Poland partly bears responsibility for the catastrophe that ensued in September 1939," he said, referring to the Nazi invasion of Poland.
He appeared to be referring to Poland's refusal to allow the transit of Soviet troops through its territory.
Mr Andreyev also said that the Soviet invasion of eastern Poland later that month was not an aggression but "to ensure the safety of the USSR" when the outcome of the German invasion of Poland was already clear.
The ambassador added that relations between Poland and Russia were at their lowest ebb since 1945, because Poland had frozen political, cultural and humanitarian contacts.