Trump in Warsaw, 80 years after WWII outbreak

US President Donald Trump, fresh from hob-nobbing with his G7 partners at a glitzy French resort town, will on Sunday attend sombre commemorations in Warsaw of the outbreak of World War II 80 years ago.

Trump will be the first US head of state to come to Poland for an anniversary of the start of history's bloodiest conflict, which claimed 50 million lives, including those of six million Jews in the Holocaust.

Few other major leaders are expected in the Polish capital, as French President Emmanuel Macron and German Chancellor Angela Merkel are not coming, while Russian President Vladimir Putin was not invited.

According to the Polish presidency, around 40 foreign delegations are expected, half of them led by heads of state.

They include Ukrainian President Volodymyr Zelensky, whose partnership is important to Poland, which believes its security depends on Ukraine remaining outside of Russia's sphere of influence.

Warsaw said Putin was snubbed this time -- unlike 10 years ago -- because of Moscow's 2014 annexation of Crimea from Ukraine.

"It would be inappropriate to commemorate the anniversary of armed aggression against Poland with the participation of a leader who is today acting this way towards a neighbour," Poland's deputy prime minister Jacek Sasin said in July.

Russia's foreign ministry responded with "bewilderment", noting Moscow's "unquestionably decisive contribution to the defeat of Hitler's Reich."