European Parliament president Antonio Tajani and Italy's Interior Minister Matteo Salvini were accused of “historical revisionism” after speaking at the event on Sunday at Basovizza, near the Slovenian border, close to where many of the victims were killed by Tito's Yugoslav partisans.
The victims were often thrown alive into deep sinkholes known as “foibe”.
Salvini made a direct comparison between “the children who died at Auschwitz and the children who died at Basovizza”
“There are no first- or second-class martyrs,” he said.
“I'm deeply concerned by inadmissible statements by senior Italian officials suggesting that the foibe (killings) represented ethnic cleansing,” Slovenian President Borut Pahor said in a letter sent on Monday to his Italian counterpart Sergio Mattarella.
“It's unprecedented historical revisionism. Fascism was a fact and its objective was destroying the Slovenian people,” Slovenian Prime Minister Marjan Sarec said in a tweet on Monday.
V soboto sem govoril o želji po potvarjanju zgodovine v Sloveniji. Enako se dogaja na italijanski strani meje. Žal s strani vidnih politikov, celo EU funkcionarjev. Zgodovinski revizionizem brez primere. Fašizem je bil dejstvo in imel je za cilj uničenje slovenskega naroda.
— Marjan Šarec (@sarecmarjan) February 11, 2019
Speaking at the same event as Salvini on Sunday, Tajani had said “thousands of innocent victims (were) killed for being Italians… by soldiers wearing a red star on their heads.”
He ended his speech by saying “Long live Italian Istria, long live Italian Dalmatia”, referring to what had been Italian territories between the two world wars and which are today part of Slovenia and Croatia.
European Parliament President Antonio Tajani. Photo: Ludovid Marin/AFP
During Monday's session of the European Parliament, Tajani said: “I'm sorry if the meaning of my words was misinterpreted. It wasn't my intention to offend anybody.”
He said his reference to “Italian” Istria and Dalmatia “was in no way a territorial claim”.
“I was referring to Istrian and Dalmatian Italian-speaking exiles, their children and grandchildren, many of whom were present at the ceremony,” he went on.
The massacres have long been a source of contention between Italy and Slovenia.
The two countries disagree on the total number of victims of the killings, with figures ranging from the hundreds to over 10,000.
The memory of the killings has also been controversial within Italy.
In the decades after the war Italy's attempts to turn the page on its Fascist history, and the crimes committed by its own forces in Yugoslavia, meant that the foibe massacres were largely commemorated only by the far-right.
It was only in 2004 that the rightwing government of Prime Minister Silvio Berlusconi initiated a national day of remembrance for the massacres.