Hungary’s leading Jewish organizations on Wednesday condemned a senior Hungarian politician over his plan to deliver a speech at a ceremony honoring a Nazi ally on International Holocaust Remembrance Day.

Sandor Lezsak, deputy speaker of the Hungarian Parliament and a member of the country’s ruling Fidesz party, is slated to give an address in Budapest on Saturday memorializing World War II-era Hungarian leader and Nazi ally Miklos Horthy on the 150th anniversary of his birth. During his rule, Horthy oversaw the deportation hundreds of thousands of Hungarian Jews to Nazi death camps.

In a letter addressed to Lezsak, Andras Heiszler, president of the Federation of Hungarian Jewish Communities, wrote that the politician’s participation in the ceremony on International Holocaust Remembrance Day “tramples on the memory of all the Hungarian victims.”

“It can only amount to the falsification of history…no state representative should contribute to the building the cult of Horthy,” wrote Heisler.

Last June, the World Jewish Congress (WJC) and the Federation of Hungarian Jewish Communities slammed pro-Horthy comments made by Hungarian Prime Minister Viktor Orban. Hours before he had hosted WJC President Ronald Lauder in the Hungarian Parliament, Orban referred to Horthy and other Hungarian leaders as “exceptional statesmen” for leading the country in the wake of the Austro-Hungarian Empire’s collapse following World War I.