JEDWABNE, Poland - Poland's president on Sunday apologized again for the murder of hundreds of Jews by their Polish neighbors 70 years ago - a World War II massacre that caused painful soul-searching in the country when it was revealed in 2000.

The date of the massacre in the village of Jedwabne, some 190 kilometers (120 miles) northeast of Warsaw, has entered Poland's remembrance calendar and the state and church leaders have apologized. But it still remains to be seen to what extent the entire nation has acknowledged cases of Polish wrongdoing against the Jews.

"The nation must understand that it also had an active role," President Bronislaw Komorowski said in a letter that was read out during the ceremony.

"Today, Poland can still hear the never-fading cry of its citizens," Komorowski said.

"Once again, I beg forgiveness."

A state investigation that closed in 2002 said that some 40 Polish men killed between 300 and 400 Jewish men, women and children in Jedwabne, in Poland's northeast, beating some to death and burning others alive in a barn. It was impossible to state the exact number of victims, the investigators said.

In 2001, then-President Aleksander Kwasniewski apologized for the crime during the first state memorial ceremony in Jedwabne. Kwasniewski attended Sunday's observances as a private individual.

For the first time, a high-ranking member of Poland's influential Roman Catholic Church also attended the ceremonies.

"Let us not be divided by the graves in Jedwabne, but let us be united in prayers for brotherhood and close ties between Poles and Jews," said Bishop Mieczyslaw Cislo, who chairs the Church's council for relations with the Jews.

Poland's bishops made an apology for the Jedwabne massacre and other crimes against Jews under the German occupation during World War II in a special ceremony of prayers in Warsaw in 2001.

At Sunday's ceremony, the Chief Rabbi of Poland, Michael Schudrich, said prayers for the dead at a monument to the massacre victims.

At the end of the ceremony, the participants placed stones on the monument, in a sign of mourning.

The probe that revealed the details of the massacre was ordered after Polish emigre historian Jan Tomasz Gross described it in his book "Neighbors" published here in 2000. According to Gross, some 1,600 Jews were killed in Jedwabne.

In 1949, a court convicted 12 Poles in the Jedwabne massacre, saying they assisted German forces in the killings, which took place after German troops occupied Poland at the start of the war.

Some 3 million of Poland's prewar Jewish population of 3.5 million were killed in the Holocaust.