The “horrific lessons” from World War II appear to be in increasing danger of being forgotten, Britain’s Prince Charles told a Jewish fundraiser on Monday.

The Prince of Wales issued the warning at a World Jewish Relief dinner where one religious leader slammed President Donald Trump’s immigration and refugee ban as “totally unacceptable.”

“In my own life, I have always tried to reach across the boundaries of faith and community; to extend a helping hand wherever one might be needed,” Charles said. “The determination of World Jewish Relief to help those in need, regardless of their faith, is one reason why I have long been drawn to it.”

Richard Stonehouse via Getty Images Prince Charles spoke at a Jewish charity fundraiser on Monday where he warned that the horrors of WWII risk being forgotten.

The evening included a speech by Chief Rabbi Ephraim Mirvis, of the United Hebrew Congregations of the Commonwealth, who went so far as to pointedly condemned Trump’s actions.

“President Trump appears to have signed an executive order which seems to discriminate against individuals based totally on their religion or their nationality,” he told the audience, according to The Telegraph. “We as Jews perhaps more than any others know exactly what it is like to be the victims of such discrimination and it is totally unacceptable.”

Watch: The Chief Rabbi @HMD_UK Ceremony, reflects on the importance of ‘action’ in response to the Holocaust & other forms of genocide. pic.twitter.com/FpSlBPs6dM — Chief Rabbi Mirvis (@chiefrabbi) January 30, 2017

Charles’ message came amid ongoing criticism over British Prime Minister Theresa May’s invitation for Trump to travel to the U.K. on an official state visit, despite global outcry over his recent actions.

More than 1.7 million Britons have signed a petition calling for Trump’s planned visit to be canceled, citing potential “embarrassment to Her Majesty the Queen.”

“Donald Trump’s well documented misogyny and vulgarity disqualifies him from being received by Her Majesty the Queen or the Prince of Wales,” it reads. “Therefore during the term of his presidency Donald Trump should not be invited to the United Kingdom for an official State Visit.”

The British public’s growing adversity to Trump is nothing new. A year ago, nearly 600,000 people signed a petition requesting that Trump, who was a presidential candidate at that time, be barred from entering the United Kingdom.