Deputy Defence Minister Kebby Maphatsoe alleged at the weekend that the country's fearless Public Protector, Thuli Madonsela, was a Central Intelligence Agency spy working to destabilise the ruling ANC party and the country.
The remarks caused an uproar and led to US ambassador Patrick Gaspard saying that he would lodge a formal diplomatic complaint.
"We categorically reject the baseless and offensive accusations," Gaspard said in a tweet.
"The ministers should spend their time improving services instead of making baseless comments," he was later quoted as telling the Cape Times.
"The government distances itself from such accusations," which do not "reflect the views and thinking of government", a minister in the presidency, Jeff Radebe, said in a statement.
"South Africa enjoys a cordial diplomatic relationship with the United States of America," he said.
Named this year by Time magazine as one of the world's 100 most influential people, Madonsela has ruffled feathers among Zuma's supporters after taking on the president over the spending of $24 million of taxpayers' money on "security upgrades" at his private rural home.
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