A high-level delegation of Muslim religious leaders has visited Auschwitz along with a Jewish group.

Organisers said it was "the most senior Islamic leadership delegation" to visit the site of a Nazi German death camp.

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The interfaith visit came four days before the 75th anniversary of the liberation of the camp by Soviet forces.

It was led by the secretary-general of the Muslim World League, Mohammad al-Issa, who called it "both a sacred duty and a profound honour."

The Mecca-based organisation, which aims to present Islam's "tolerant principles", posted images of the visit to its social media feeds.

"The unconscionable crimes to which we bear witness today are truly crimes against humanity. That is to say, a violation of us all, an affront to all of God’s children," said al-Issa.

The delegation included 62 Muslims, including 25 prominent religious leaders from more than two dozen countries, as well as members of the American Jewish Committee.

A post of the Muslim World League's Twitter feed showed Jews and Muslims praying side by side at the site in southern Poland.

Al-Issa's outreach to Jewish organisations coincides with a broader alignment of interests and ties emerging between the Arab Gulf states and Israel, which share a common foe in Iran.

On Friday, members of the delegation will visit the POLIN Museum of the History of Polish Jews in Warsaw and attend Muslim and Jewish religious services there.

Meanwhile, world leaders voiced alarm at resurgent anti-Semitism on Thursday as they gathered at Israel's national Holocaust Memorial to mark the liberation of the Nazi death camp.

Israeli Prime Minister Benjamin Netanyahu and US Vice President Mike Pence also castigated Iran in their speeches to the World Holocaust Forum, accusing it of rabid anti-Semitism and of seeking Israel's destruction.

Leaders of Russia and France looked closer to home in lamenting the killing of six million Jews in Europe during World War II by the Nazis and pledging to combat rising anti-Semitism.

German President Frank-Walter Steinmeier told the conference at the Yad Vashem memorial centre that he bowed his head in "deepest sorrow [for] the worst crime in the history of humanity" committed by his countrymen.