Prince Charles said the world is in danger of forgetting the lessons of the Second World War.
His words came during a fundraising event in London for the World Jewish Relief charity, which is working with people who are fleeing Syria and seeking new lives in Greece, Turkey and the UK.
The prince told the invited guests that he admired the WJR for reaching out beyond its own community to help anyone, regardless of their faith.
He said: "The work of World Jewish Relief enables us to rally together, to do what we can to support people practically, emotionally and spiritually, particularly at a time when the horrific lessons of the last war seem to be in increasing danger of being forgotten."
Chief Rabbi Ephraim Mirvis criticised US President Donald Trump for his "totally unacceptable" travel ban and received applause.
The Chief Rabbi said: "Not much hope from the United States of America, of all countries, where President Trump appears to have signed an executive order which seems to discriminate against individuals based totally on their religion or their nationality.
"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."
During his speech Prince Charles also recalled the "indescribable persecution" suffered by Holocaust survivor Ben Helfgott, who faced the horrors of the Buchenwald concentration camp but went on to captain Britain's weightlifting team at the 1956 and 1960 Olympic Games.
The charity was founded in 1933 to support people fleeing persecution from Nazi Europe.
It now supports vulnerable people in 18 countries through activities including disaster relief, employment skills and providing older people with food, medicine and companionship.