More than a million European Jews perished at the site located in then German-occupied southern Polish town of Oswiecim during World War II.

Pence passed through the Auschwitz camp's infamous wrought-iron “Arbeit macht frei” (“Work makes you free”) gate before laying a wreath at the death wall where the Nazis executed thousands of people.

Accompanied by his wife Karen and Poland's President Andrzej Duda and First Lady Agata Kornhauser-Duda, Pence then stood, head bowed in silent homage.

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The group visited the exhibit of human hair and personal effects of victims inside an adjacent barrack block prior to the wreath-laying. 

US President Donald Trump's son-in-law and adviser Jared Kushner was also  present.

Later, at the nearby twin death camp of Birkenau, Pence knelt and placed a rose on the running board of a train wagon on tracks that the Nazis used to bring prisoners to the camp from across Europe. 

The American officials were in Warsaw this week for a two-day conference on the Middle East co-hosted by Poland and the United States and focused on 
isolating Iran while building Arab-Israeli ties.

Speaking at the event, Pence accused Tehran of planning a “new Holocaust” with its opposition to Israel and regional ambitions in Syria, Lebanon, Iraq and Yemen.

Israeli Prime Minister Benjamin Netanyahu also attended as did representatives of Arab states, but Russia and Iran did not, with Tehran slamming the meeting as being “dead on arrival” and having “empty results”.

Of the more than 1.3 million people held by Nazi Germany at Auschwitz, some 1.1 million mostly Jewish prisoners perished, either in the gas chambers or by starvation or disease. 

Historians estimate that up to 150,000 ethnic Poles were also held at Auschwitz. Used as slave labourers, half died at the camp.

SEE ALSO: 'Hell on earth was a German creation' says foreign minister on visit to Auschwitz

European Roma were also targeted for annihilation. Around 23,000 were deported to Auschwitz, of whom only 2,000 survived, according to estimates. 

The Nazis killed six million of pre-war Europe's 11 million Jews and more than half of its roughly one million Roma. 

Black Germans, homosexuals, Jehovah's Witnesses and the mentally and physically disabled were also persecuted as “undesirables”.