June 18 (Reuters) - Israeli Foreign Minister Gideon Saar said on Thursday he was severing "all contact" with European Union foreign policy chief Kaja Kallas over what he said were remarks attributed to her comparing Israel to apartheid-era South Africa.

In a post on social media, Saar said Kallas had reportedly "compared Israel to the racist apartheid regime" during a visit to Mexico and that as a result he was severing contact until she retracted the comments.

There was no immediate comment from Kallas' office.

In subsequent posts on X, Saar shared posts from other accounts that mentioned or referenced a June 12 report by European news website Euractiv that cited unnamed officials and diplomats as saying that during her visit to Mexico last month, Kallas had compared Israel's treatment of Palestinians in the West Bank and Gaza to that of the policies of South Africa under apartheid, a system of legally enforced racial segregation.

The European Union has criticised Israel's expansion of Jewish settlements in the West Bank, widely viewed as illegal under international law and an obstacle to Israel-Palestinian peace and the establishment of a Palestinian state.

In May, the EU sanctioned three individuals and four entities that it said were responsible for "serious and systematic human rights abuses against Palestinians in the West Bank". In response, Saar at the time said Israel firmly rejected the decision.

The EU has also criticised Israel's conduct in the war in Gaza while reaffirming its right to defend itself. But the bloc's 27 member states are divided, with some highly critical of Israel and others maintaining close ties.

On Thursday, Saar accused Kallas of "acting obsessively and with blatant unfairness toward the State of Israel".

(Reporting by Alexander Cornwell; editing by Barbara Lewis, William Maclean)