"The memory of the shady sides of the occupation period also belongs to the commemoration of the 60th anniversary of the Liberation," Rasmussen said at a ceremony at a war monument in Copenhagen, a day before the May 5 anniversary of his country's liberation by Allied powers.

"This why I want ... on behalf the government and therefore of the Danish state to express my regret and apologies for these acts," he said. "An apology cannot change history. But it can contribute to recognize mistakes made in history and hopefully help future generations to avoid similar mistakes in the future."

Rasmussen said the apology concerned Jews, but also all others who were "handed over to an uncertain fate in Hitler's Germany with the active cooperation of the Danish authorities."

The extradition of innocent people to Nazi Germany was both "shameful" and "a stain on Denmark's otherwise good reputation," he said.

Recent research showed that some 20 Jews were expelled from Denmark to their certain death in Germany.

The apology, which had been expected after the prime minister publicly blasted his country's wartime record in an interview with the daily Berlingske Tidende, came as Danes, six decades after their country's collaboration with Nazi Germany, remain bitterly divided over whether the kingdom had any choice when faced with the might of its aggressive neighbour.

Occupied by German forces in just a few hours with little resistance on April 9, 1940, Denmark collaborated with the invader in the following years until August 29, 1943, when acts of resistance and insurrection coupled with stricter German demands ended that policy.

Queen expressed understanding

In stark contrast to the prime minister, Denmark's Queen Margrethe II has expressed her comprehension of the collaboration policy.

"One way or another, one understands it well," she admitted in a recently published biography "Margrethe." "It was like there was no other way, and given the situation we got ourselves into, we could not have done differently," she said.

In the interview, Rasmussen meanwhile called the collaboration policy "naive" and "dishonorable," and condemned the "elite then in power, which was not just neutral, but led an extremely active policy of accommodation, with wide-reaching consequences for Jewish refugees and forced laborers."

Thousands of Danish companies, including arms manufacturer Dansk Industri Syndikat, exploited the policy of collaboration for profit and cooperated more closely with Nazi Germany than anybody demanded of them, according to recent research produced by a group of historians, led by Ole Lange. Without being pressured by either the occupying power or their own government, these companies adapted their production to German needs, often using forced Soviet or Polish labor on a large scale, the research shows.

Rasmussen opportunistic?

But some critics have charged that Rasmussen, 52, who has been critical of Denmark's wartime regime in the past, failed to understand the reality of the 1940s, and opportunistically tried to present himself as a moralistic leader. Historians, while leaving little doubt as to the extent of corporate collusion with Germany, still warn that Rasmussen should not draw conclusions of guilt too easily. "The prime minister is ignorant of the situation at the time," Lange said.

Bo Lidegaard, a historian and author of a new book "The Battle for Denmark 1933-1945," told AFP that "the more one learns about that period, the more difficult it becomes to condemn the policy of collaboration." Denmark obtained much from Nazi Germany during the occupation years, including promises of sovereignty and territorial integrity, he said. The United States and Britain, he added, actually wanted Denmark to continue to collaborate to avoid an outright hostile occupation of the kingdom.

"It was judged important that Denmark should keep as much as possible of its production and let Germany have as little as possible. And Britain called on its agents in Denmark not to provoke a Nazi takeover of Denmark which would have been against the allies' interests. The Americans were exactly of the same opinion," he said.