A new diplomatic crisis between Poland and Israel has erupted following the death of a Polish aid worker in Gaza, with the Polish president denouncing a comment by the Israeli ambassador as “outrageous” and the Foreign Ministry in Warsaw saying it was summoning him for a meeting.

Polish 35-year-old Damian Sobol was among seven people who were killed by a strike while delivering food to Palestinians with the charity World Central Kitchen. Israel has called the incident a “mistake” that followed a misidentification. The charity said its vehicles were clearly marked.

Amid shock in Poland over the death of the aid worker, Israel’s ambassador to Poland, Yacov Livne, pushed back at what he said were attempts by the “extreme right and left in Poland” to accuse Israel of “intentional murder in the attack.”

He said on social media on Tuesday that “antisemites will always remain antisemites, and Israel will remain a democratic Jewish state that fights for its right to exist. Also for the good of the entire Western world.”

Polish President Andrzej Duda called the comment “outrageous” and described the ambassador as “the biggest problem for the state of Israel in relations with Poland.”

Duda said authorities in Israel have spoken about the tragedy “in a very subdued way,” but added, “Unfortunately, their ambassador to Poland is not able to maintain such delicacy and sensitivity, which is unacceptable.”

Prime Minister Donald Tusk, while a political opponent of Duda’s, voiced a similar position on Thursday.

He said that the comment was unacceptable and had offended Poles and that the ambassador should apologize.

“If the ambassador decides to make public appearances in our media, he should use this opportunity to offer a simple, human apology,” Tusk said.

The deputy foreign minister was quoted in Polish media as saying that Livne was summoned to a meeting on Friday morning.

The deadly strike in Gaza reignited tensions between the two nations that have seen a number of diplomatic rows over the past years, notably on Holocaust history and remembrance — though all under the previous, hard-right government.