Russia and Poland are sniping at each other on Twitter over who actually invaded Poland in WWII

Wu Zhuang / Xinha via Getty Images

A soldier salutes on a tank during the Victory Day parade in Moscow, May 9, 2017.

• The Russian Embassy in South Africa subtweeted the Polish Embassy in the UK on Tuesday, denying responsibility for the 1939 invasion of Poland, which started World War II.
• The Soviet Union and Nazi Germany signed a nonaggression pact days before Germany invaded Poland and about three weeks before the Soviets invaded.
• The pact included secret provisions for carving up parts of Europe, including Poland, into Soviet and Nazi spheres of influence.
• Russian President Vladimir Putin was not invited to a ceremony for the 80th anniversary of the invasion, in part because of Russia's annexation of the Crimea in 2014.
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An 80-year-old conflict was revisited on Tuesday, as the Polish Embassy in the UK commemorated the anniversary of the Soviet Union's invasion, which came two weeks after Germany invaded and started World War II.

The Russian embassy in South Africa didn't let Poland's tweet go without a denial.

"The USSR is often accused of invading Poland. Wrong!" the embassy tweeted. "The Nazis attacked Poland on 1 September. It was not until 17 September, with Polish government fleeing & forces defeated, that the Red Army entered 'Polish territories' - Belarus and Ukraine occupied by Warsaw since 1920."

The USSR and Germany had signed the Molotov-Ribbentrop Pact, a neutrality agreement, just days before Germany invaded Poland on September 1, 1939.

Germany invaded Poland from the west, the USSR invaded from the east, and the two carved up Polish territory between them, although the Soviet Union did not formally declare war.

Unbeknownst to the Polish, the USSR and Nazi Germany had secretly discussed how they would divide parts of Europe, including Poland, giving the USSR the territory it felt it had lost after the Treaty of Riga ended the Polish-Russian War in 1921.

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Russia has attempted to rewrite history, saying World War II didn't actually start until 1941 and referring to it as the Great Patriotic War. This year, Russia tried to justify the existence of the Molotov-Ribbentrop pact by claiming European countries didn't sufficiently stand up to Hitler or offer Germany more favorable alternatives, according to the Associated Press.

Russia's response to the Poland tweet takes on more significance in light of its annexation of Crimea in 2014, a move reminiscent of its invasion of Poland in 1939 - in both cases, Moscow denied or obfuscated the invasion but claimed the lands being invading belonged to it anyway.

Russian President Vladimir Putin was not invited to a commemoration of the invasion of Poland this year because of the annexation of Crimea and his increasingly authoritarian rule.