Germany and the Soviet Union were co-responsible for the outbreak of World War II, U.S. Ambassador to Poland Georgette Mosbacher said in a tweet on Monday.
Mr Georgette was responding to recent claims made by Russian President Vladimir Putin about the origins of the conflict.
The ambassador wrote: “Dear President Putin, Hitler and Stalin colluded to start WWII.
“That is a fact. Poland was a victim of this horrible conflict.”
In comments made over the past week, Putin denied that the Soviet Union played a role in launching WWII and attempted to shift some of blame for the conflict onto Poland.
He also rejected the notion that Soviet Russia invaded Poland in 1939 and suggested that Poland was complicit in Hitler’s Holocaust plans, calling the Polish pre-WWII ambassador to Germany an “anti-Semitic pig”.
Earlier this month, Putin criticised a European Parliament resolution that stated that the 1939 non-aggression pact between Nazi Germany and the Soviet Union “paved the way for the outbreak of World War II”.
Putin’s comments triggered an outcry in Poland, where the government summoned the Russian ambassador to express its disapproval.
Late on Sunday, Polish Prime Minister Mateusz Morawiecki said in a statement that it was unacceptable to cast perpetrators as victims.
Morawiecki said that the Russian president “has lied about Poland on numerous occasions, and he has always done it deliberately.
“This usually happens when Russian authorities feel international pressure related to their activities.”