JOHANNESBURG, Nov. 21 (Xinhua) -- South African President Cyril Ramaphosa rejected handing over the Group of 20 (G20) presidency to a low-ranking U.S. diplomat, the president's office said Thursday, amid escalating diplomatic tensions between Pretoria and Washington.

"The President will not hand over to a charge d'affaires," presidential spokesperson Vincent Magwenya wrote on social media X.

The dispute came after U.S. White House Press Secretary Karoline Leavitt on Thursday criticized Ramaphosa, accusing him of "running his mouth" over the U.S. boycott of the G20 summit.

Leavitt confirmed that a U.S. delegation will attend the handover ceremony at the end of the summit, but said Washington will not take part in the G20 discussions.

Marc D. Dillard, charge d'affaires at the U.S. embassy in Pretoria, is expected to lead the U.S. delegation at the upcoming G20 Leaders' Summit.

In diplomatic practice, a charge d'affaires is the lowest-ranking head of mission, usually appointed only when a country does not have an ambassador in place. Unlike an ambassador or minister, a charge d'affaires does not present credentials to the host head of state and is generally viewed as a temporary or junior-level representative. ■