Poland has demanded that Israel officially apologize for provocative remarks made by the occupying regime’s foreign minister against the Poles in a row that prompted the European country to withdraw from a summit in Israel.

Acting Israeli Foreign Minister Israel Katz said in an interview with Channel 13 over the weekend that “Poles suckle anti-Semitism with their mothers’ milk,” repeating an old quote from Yitzhak Shamir, a former Israeli prime minister and Holocaust survivor.

Katz also alleged on Sunday, the same day he was appointed as the regime’s interim foreign minister, that “there were many Poles who collaborated with the Nazis.”

The comments infuriated Warsaw, prompting its senior officials on Tuesday to demand that Israeli authorities formally make an apology over the allegations.

Israeli authorities must “reject this declaration… and apologize,” said Poland’s Deputy Foreign Minister Szymon Szynkowski, adding that “this is not something that can be left without a response.”

Separately on Tuesday, Polish Prime Minister Mateusz Morawiecki’s chief of staff, Marek Suski, said if no apology was forthcoming, “relations will really take a frosty turn.”

A day earlier, Morawiecki lad lambasted the comments as “racist and unacceptable,” adding that Katz was “trying to insult the Poles by distorting history.”

On Friday, Poland summoned Israel’s ambassador to Warsaw for a dressing down over the comments made by Israeli Prime Minister Benjamin Netanyahu, who on February 14 appeared to accuse the European country of collaborating with the Nazi Germany in carrying out what is said to be the Holocaust.

Later in the day, Israeli authorities claimed that Netanyahu’s comments at a press conference in Poland had been misquoted and misunderstood, and thus convinced Warsaw and alleviated its concerns, thereby ending the short-lived spat.

However, Katz’s provocative comments on Sunday resurrected the spat and promoted Morawiecki on Monday to announce that no Polish officials would attend a planned summit between a group of four Central European countries, the Czech Republic, Hungary, Poland and Slovakia, known as the Visegrad Four (V4), in Israel this week.

The V4 summit, which aims to further European integration as well as advancing military, economic and energy cooperation with one another, was cancelled on Monday after Poland’s withdrawal.

Sensitivities are high in Poland over the issue of its actions during the so-called massacre of Jews, known as the Holocaust.