The U.S. State Department has issued a travel alert to U.S citizens living in South Africa or traveling there for the World Cup.
The State Department said it would make any information public on "a specific and credible threat."
U.S. citizens were advised to keep car doors and windows locked while driving and not to leave valuables in plain view or to wear expensive jewelry.
The alert said public transportation is "poorly developed" and advised using rental cars or private transport instead. And when stopping at intersections at night or in isolated areas, it suggested leaving room for a "quick exit."