FUERSTENBERG, Germany (AP) — Officials in Germany are solemnly commemorating the liberation of two Nazi concentration camps 70 years ago in the closing days of World War II.

Poland's first lady, Anna Komorowska, joined in remembrance activities Sunday at the site of the Ravensbrueck women's camp in northern Germany. Many of the prisoners came from Poland.

Ceremonies also were taking place at the former Sachsenhausen camp near Berlin.

The U.S. Holocaust Memorial Museum says 30,000 to 50,000 people died at Sachsenhausen, where inmates included Jews, Poles, Soviet prisoners of war and opponents of the Nazis. More than 130,000 women were imprisoned in Ravensbrueck; 20,000 to 30,000 died there.

Sachsenhausen was liberated on April 22, 1945, Ravensbrueck on April 30. Beforehand, Nazi officials forced thousands from the camps into death marches that killed many inmates.

Meanwhile, Poland's Foreign Ministry urgently summoned U.S. Ambassador Stephen Mull on Sunday to "protest and demand an apology," saying the FBI director suggested that Poles were accomplices in the Holocaust.

James Comey made the remarks in an article about the Holocaust that was published by The Washington Post on Thursday. It was adapted from a speech he gave Wednesday at the U.S. Holocaust Memorial Museum.

After meeting with Deputy Foreign Minister Leszek Soczewica on Sunday, Mull said he will be contacting the FBI. Earlier in the day, Mull said that Comey's words were "wrong, harmful and offensive," and didn't reflect the U.S. administration's views.

Nazi Germany occupied Poland and ran death camps here from 1939-45, killing millions of Jews, Poles and people from other countries.