U.S. President Donald Trump's administration on Thursday vehemently denied South Africa's announcement that the United States was ending a boycott of this weekend's G20 summit in Johannesburg, saying no U.S. official would take part in talks.

South African President Cyril Ramaphosa earlier Thursday described an 11th-hour about-turn by the Trump administration, which had relentlessly attacked South Africa over the treatment of white minority farmers by the post-apartheid government.

The White House said the U.S. ambassador would attend but only for a handover ceremony as the United States will next year host the summit of the club of global economic powers, at a golf club owned by Trump in Florida.