The US decision to expel South Africa's ambassador was "regrettable," the office of the South African president said Saturday, after Washington's top diplomat accused the envoy of hating America and President Donald Trump.

Secretary of State Marco Rubio said Friday that South Africa's ambassador, Ebrahim Rasool, was "no longer welcome" in the United States.

Rasool is "a race-baiting politician who hates America and hates @POTUS," Rubio posted on X, referring to Trump by his White House X account handle. "We have nothing to discuss with him and so he is considered PERSONA NON GRATA." South Africa's presidency said in a statement it had "noted the regrettable expulsion" and urged "all relevant and impacted stakeholders to maintain the established diplomatic decorum in their engagement with the matter." "South Africa remains committed to building a mutually beneficial relationship with the United States of America," the presidency said.

The expulsion of the ambassador- a very rare move by the United States- is the latest development in rising tensions between Washington and Pretoria.