WARSAW, Poland (AP) — Poland’s prime minister said Wednesday he wasn’t completely satisfied with a White House explanation that President Barack Obama misspoke when he referred to “Polish death camps” during a ceremony honoring a World War II hero, saying he wants a “stronger, more pointed” response.

The phrasing is considered hugely offensive in Poland, where Nazi Germany murdered Poles, Jews and others in death camps it built during World War II on Polish and German territory. Poles have responded with outrage, maintaining Obama should have called it a “German death camp in Nazi-occupied Poland,” to distinguish the perpetrators from the location.

Donald Tusk said he was accepting a White House explanation that Obama misspoke but was still waiting for a “stronger, more pointed reaction” that could eliminate the phrasing “once and for all.” Tusk said it was a “matter of the U.S.’s reputation.” He hinted it should include facts about Nazi Germany’s brutal occupation of Poland.

Former President and Solidarity founder Lech Walesa said the phrase confused henchmen with their victims but that Obama’s mistake might prevent similar statements by others.

The White House said the president misspoke Tuesday in bestowing the Medal of Freedom posthumously on Jan Kozielewski, alias Karski, a Polish emissary who in 1943 alerted Allied leaders to mass killing of Jews. In order to gather first-hand evidence he risked his life and was secretly smuggled into the Warsaw Ghetto and a death camp.

Anxious to quell the controversy, the White House also noted that the president had visited the Warsaw Ghetto Memorial while in Poland and that he has repeatedly discussed the bravery of Poles during World War II.

The Polish Embassy in Washington, on its website, has a “how-to guide” on concentration camps that states that references to Polish death camps are “factually incorrect slurs” that should be corrected.