European Union chief Ursula von der Leyen marked Roma Holocaust Memorial Day on Sunday with an appeal to EU member states to protect today's minorities from discrimination and racism.
And she paid tribute to Raymond Gureme, a French Roma survivor of the internment camps, who died in May, aged 94.
"We consider it a moral duty to acknowledge and remember all those who suffered under the Nazi regime: among those people were the Roma," Von der Leyen said in a joint statement with Commission Vice President Vera Jourova and Equality Commissioner Helena Dalli.
In addition to more than six million Jews who died at the hands of the Nazis during World War II, half a million Roma -- about a quarter of their population -- suffered the same fate.
"Remembering their persecution reminds us of the need to tackle the challenges they still face today and which are too often overlooked," the statement said.
"Europe has a duty to protect its minorities from racism and discrimination," von der Leyen said.
"As the number of survivors and witnesses of these atrocities is dwindling, it is our duty, now more than ever, to continue their work of memory and to pass on their testimonies," their statement added.
- Discrimination continues -
"We must replace anti-gypsyism with openness and acceptance, hate speech and hate crime with tolerance and respect for human dignity, and bullying with education about the Holocaust," it said.
For his part, European Parliament president David Sassoli marked the day with a call for active remembrance, saying in a Tweet: "Remembering must never become a hollow act, it requires constant effort and will."
Echoing von der Leyen, he said anti-Roma prejudice should be fought "at every level", and urged Europeans to "continue to protect the values that underpin EU integration".
Von der Leyen, in her tribute to Gureme, described him as "a historical figure of the French Gypsy community".
"He will be remembered for fighting to the very end for the rights and dignity of Roma, for his combat against all forms of racism; and for his struggle for the recognition of the Romani Holocaust," she added.
To this day, Roma children are segregated in mainstream schools in several central and eastern European countries, the UN educational agency UNESCO said in a report in June.
In Hungary, segregation of pupils on ethnic grounds is illegal but the practice is widespread, particularly in areas with large populations of Roma, the country's largest ethnic minority at around seven percent of the 9.7 million population.
August 2 was designated the European Roma Holocaust Memorial Day in 2015.