Russia and Poland in spat over World War Two cause
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.
Relations between Poland and Russia have been poor in recent years, with Poland one of Moscow's sharpest critics over its intervention in Ukraine.
The row comes a day after Poland's ambassador in Moscow was summoned over the vandalising of graves of Soviet soldiers in a Polish village.
Poland has also condemned the desecration at the Milejczyce cemetery.
'Lack of respect'
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.
The Polish Foreign Ministry said Mr Andreyev had "undermined historical truth".
"We take it as a lack of respect for the memory of the victims of the NKVD [Soviet secret police]," it said in a statement, referring to the repression which followed the Soviet invasion.