The man has not been identified yet.
Oskar Groening was sentenced in July 2015 to four years in prison for his role in the murder of 300,000 Hungarian Jews at the camp in Poland.
An Israeli reserve military officer was detained in the United Kingdom over accusations of war crimes.
The White House said efforts to have Israel charged with war crimes at the International Criminal Court are “counterproductive” and would be opposed by Washington.
The Palestinian Authority joined the International Criminal Court on Wednesday, potentially giving the world’s permanent war crimes tribunal jurisdiction over future crimes in the region.
The Palestinians plan to file their first complaints in International Criminal Court on April 1.
A United Nations inquiry into possible war crimes in the Gaza conflict will produce its report on time next month despite the resignation of its chairman, officials said on Tuesday, brushing aside a demand from Israel’s prime minister to shelve it.
The Palestinian Islamist group Hamas said on Saturday it welcomed a decision by the International Criminal Court to launch an inquiry into possible war crimes in the Palestinian territories.
Israel’s top military officer said on Thursday he was disappointed rather than worried about a Palestinian move to join the International Criminal Court, calling it unnecessary because Israel could investigate complaints itself.
The International Criminal Court acknowledged that it received a signed document stating that the Palestinian government accepted jurisdiction of the court.