Trump has given priority to Afrikaners, a white minority group he says is being persecuted. South Africa has objected to his characterisation.
Confederation of African Football president Patrice Motsepe has "zero tolerance" for corruption, which he says is "worse than cancer".
The foreign minister says the accusations, involving children, were investigated and found to be unsubstantiated.
The state department has also authorised non-emergency embassy staff to leave on security grounds.
Ex-President Yahya Jammeh's 22-year rule was known for enforced disappearances and extrajudicial killings.
Very few people are ever prosecuted following terror attacks with suspects often held without trial.
The government usually refrains from commenting on the participation of its citizens in the conflict.
The presidency says it is taking action as it fears fuel shortages could lead to public disorder.
The ruling party has unveiled a draft law that strips voters of the chance to elect the president.
The ruling party has unveiled a draft law that strips voters of the chance to elect the president.