ZURICH—In the latest in a string of incidents betraying tense relations between Liechtenstein and Germany, Prince Hans-Adam II of Liechtenstein has called present-day Germany a "fourth" Reich, the International Herald Tribune reports. The prince included his comment in a letter to the Jewish Museum in Berlin explaining why he would not loan a painting for an exhibition of artworks stolen by the Nazis.

"I would really have liked to support the exhibition, as our collection was itself a victim of art theft during World War II and afterwards, if only it wasn't in Germany," he said in the letter, which was published Thursday by the Swiss newspaper Tages-Anzeiger.

The letter goes on to say: "As far as German-Liechtenstein relations are concerned, we are waiting for better times, which I am hopeful for, as we have already survived three German Reichs in the past 200 years and I hope we will also survive a fourth one."

The Jewish Museum received the letter in June after requesting the loan of Frans Hals's Portrait of a Man for its exhibition.

Eva Sšderman, a spokeswoman for the museum, responded to the letter by saying "If you describe the Federal Republic of Germany as a 'Fourth Reich,' and thereby suggest parallels between the current country and the Third Reich, you are trivializing the severity of National Socialism in a most irresponsible way."

In February, Germany began to investigate thousands of its citizens suspected of putting savings in Liechtenstein banks to evade taxes. Liechtenstein decried the investigation, saying that Germany was illegally acquiring secret bank information from an informant. In March, Prince Alois, Hans-Adam's son, canceled a loan to Munich's Neue Pinakothek museum in the wake of the disagreement.

Salomon Korn, vice president of the Central Council of Jews in Germany, has said he expects an apology from Prince Hans-Adams to Michael Blumenthal, the Jewish Museum's head and a former U.S. Treasury secretary whose family fled Nazi Germany in 1939.

The prince's office issued a statement saying that he had not meant "to belittle the atrocious events of the Third Reich."