WARSAW (AFP)---Accusing Poland of having forced out Jews who survived the Holocaust, US-based historian Jan Gross has sparked a backlash ahead of the Friday launch of the Polish edition of his book "Fear".

"Until now, no one has ever written like Gross (...) about the attitude of Poles towards the Jews," said historian Pawel Machcewicz, a fierce critic of the Polish-born Jewish writer.

Machcewicz slammed Gross for using the term "ethnic cleansing" to describe the post-1945 expulsion of most Germans and Ukrainians from Poland, and the pressure on Jewish Holocaust survivors to leave the country.

"I’m afraid this book will harm Polish-Jewish relations," said Father Adam Boniecki, the editor of Tygodnik Powszechny, a respected weekly catering to Poland’s liberal-leaning Roman Catholic intelligentsia.

Boniecki also found fault with what he termed the "accusatory tone" of the book.

More virulent critics accuse Gross of avenging his own past.

Born in Warsaw in 1947, he emigrated to the United States after Poland’s ruling communist party launched an anti-Semitic campaign in 1968.

A professor at Princeton University in the United States, Jan Gross already shook Poland in 2001 with his book "Neighbours". In it he revealed that in 1941, during the Nazi occupation, several hundred Jews -- an estimated 340 to 1,600 -- were massacred or burned alive by their Polish neighbours in the small Polish town of Jedwabne.

"Neighbours" lead then Polish President Aleksander Kwasniewski to apologise to Jews worldwide for the crime.

It also provoked an unprecedented and broad debate in Poland about the complex relationship before and after World War II between Jewish citizens of Poland and the overwhelmingly Catholic majority.

Published in English in 2006, "Fear" breaks no new historical ground. It focuses on the July 4, 1946 Kielce Pogrom in which 40 survivors of the Holocaust were massacred by the local Polish population after false rumours spread that Jews had killed a Polish boy.

The brutal attack took place just over a year after the end of Nazi  occupation of Poland.

In the immediate post-war period, between 600 and 3,000 of the 300,000 Jews who had survived the Holocaust were killed in pogroms or murdered one-by-one, according to Poland’s Institute for National Remembrance (IPN), charged with investigating Nazi and communist-era crimes.

Poland's image undermined

While Jan Gross takes care to point out that thousands of Poles risked their lives to save Jewish neighbours from the Nazis, the mounting toll of anti-Semitic historic detail in "Fear" undermines Poland’s self-image as the heroic and the principle martyr of the war.

He points to Polish "society’s violently expressed desire to render the country ’Judenrein’" (Jewless).

For Gross, Poland’s communist regime took over where the Nazis left off in the annihilation of three million of the 3.5 million Jews who lived in Poland before the war.

"Poland’s communist rulers fulfilled the dream of Polish nationalists by bringing into existence an ethnically pure state," Gross writes.

He ascribes Poles’ rejection of Holocaust survivors who re-surfaced after hiding out in wartime Poland or taking refuge in the Soviet Union to the Poles’ desire to keep abandoned Jewish properties and guilt over having profited from the riches left by Holocaust victims.

IPN director Janusz Kurtyka has gone so far as to reject the professional credentials of the Princeton professor. "Gross isn’t an historian," he said Thursday.

"Above all he plays on emotions with a very limited range of sources, interpreted in a biased fashion."