Europe's leaders mark 70 years since WWII, old wounds remain...

GDANSK, Poland (AFP) - – Former World War II enemy nations Tuesday marked the anniversary of the outbreak of history's bloodiest conflict, 70 years after the first salvo on the shores of the Baltic Sea.

At a memorial ceremony, German Chancellor Angela Merkel said her country's Nazi-era invasion on September 1, 1939, opened the "most tragic chapter" in European history.

Merkel joined more than a dozen leaders as well as war veterans at Westerplatte, a Polish naval base which saw the war's first battle.

The ceremony underlined how Europe has healed deep divisions in the intervening decades. But old wounds were clear to see amid fresh disputes over the war's legacy, especially between Russia and Poland which were alternately foes and allies during the six-year conflict.

The leaders, including Russian Prime Minister Vladimir Putin, Poland's President Lech Kaczynski and Prime Minister Donald Tusk, carried candles to the graves of Polish soldiers who were among the first of an estimated 50 to 60 million people to perish around the globe during World War II.

For Poles, Westerplatte symbolises courage in the face of overwhelming odds.

Its 180 defenders held out for seven days while the base was assaulted by 3,500 Germans, pounded by a battleship and bombed from the air. Sixteen Poles, and around 350 Germans, were killed.

Near the imposing granite monument to the defenders, Polish marines fired three salutes.

"We must never forget the heroism of the soldiers who fought here," Sebastien Blawat, an 18-year-old Polish Navy cadet, told AFP.

His colleague Piotr Scholla, also 18, added: "They didn't give up. Poles don't give up."

In her speech, Merkel recalled that the "war unleashed by Germany resulted in immeasurable suffering to many peoples -- years of deprivation of rights, of humiliation and destruction."

The Polish army, outnumbered by more than two to one, surrendered a month after the invasion, and a brutal Nazi occupation began.

Almost six million Polish citizens perished in the war. Half of the six million European Jews who died in the Holocaust were from Poland.

At a pre-dawn ceremony, Tusk spoke of how the memories and bitterness of 70 years ago still burned.

"We are here to remember who in that war was the aggressor and who was the victim, for without an honest memory neither Europe, nor Poland, nor the world will ever live in security," said Tusk.

Bogdan Kolodziejski, who was 10 when the war began and became a resistance courier, recalled those dark days.

"I've never forgotten the day the Germans marched into Warsaw, singing at the top of their voices," he told AFP.

Many Poles harbour bitterness towards Russia over the Molotov-Ribbentrop Pact of August 23, 1939, under which Germany and the Soviet Union secretly agreed to carve up Poland between them. The Red Army invaded on September 17, and executed thousands of Polish POWs in 1940 in the notorious Katyn massacre.

Putin acknowledged the pact was a mistake but said all attempts to appease the Nazis were "morally unacceptable" -- an apparent reference to the 1938 Munich agreement in which Britain and France told Adolf Hitler they would not object to the Nazi annexation of parts of the former Czechoslovakia.

Britain and France, bound to Poland by military pacts, declared war on Germany on September 3, 1939, pulling their vast empires into the conflict.

For Russia, what is known as the "Great Patriotic War" started on June 22, 1941, when the Nazis tore up the pact and invaded. Suddenly the Soviet forces found themselves as Poland's allies.

Around 8.6 million Soviet soldiers and nearly 28 million civilians were killed in the war, which ended in Europe with Germany's crushing defeat in 1945.

Merkel pointed to the continent's post-war recovery which should be seen as a source of pride.

"Europe ... has transformed itself from a continent of terror and violence into a continent of freedom and peace. That this was possible is nothing more and nothing less than a wonder," she said.

Other nations "stretched out the hand of forgiveness, and we took it, with thanks."