GDANSK, Poland — The outbreak of World War II 75 years ago shows why Europe must put an end to the war in Ukraine now, Poland’s prime minister said Monday.

Prime Minister Donald Tusk, chosen by EU leaders to be the next president of the European Council, spoke at the Westerplatte peninsula on the Baltic coast, where some of the first shots of World War II were fired on September 1, 1939, by an attacking Nazi German warship. Two weeks later Soviet troops invaded from the east, acting on a Moscow deal with Germany to carve up Poland.

More than five years of brutal, global war followed, taking the lives of tens of millions of people.

“Today, looking at the tragedy of Ukraine, at war — because we should use this word — in the east of our continent, we know that September 1939 must not be repeated,” Tusk said.

He said the lesson that Europe should draw from its past “must not be a lesson of naive optimism” because the security of the continent requires “courage, imagination and resolute action.”

Europe’s security in the face of armed conflicts is the top priority for a NATO summit opening open in Wales on Thursday. Mindful of their painful history, Poland and the Baltic States are calling for a sizeable, permanent presence of NATO troops on their territory.

“From Westerplatte to all of Europe’s capitals and to the NATO summit, we will take this call for our European, trans-Atlantic solidarity to have a practical dimension,” Tusk said. “There is still time to stop all those in Europe and in the world for whom violence, force, aggression are again becoming an arsenal of political activity.”

German President Joachim Gauck is to join the WWII observances later Monday.

Copyright 2014 The Associated Press