South Africa said on Wednesday it was monitoring a number of people linked to a reported threat to U.S. interests, but was satisfied that no one in the country faced any imminent danger.
The U.S. Embassy warned its citizens on Tuesday of a possible attack by "extremists", a rare security alert in a stable democracy seldom associated with Islamist militancy.
South African State Security Minister David Mahlobo told Talk Radio 702 on Wednesday the U.S. embassy had shared information linked to the warning with his officials.
He referred to "the information that they have shared with us and the individuals concerned that we are following".
"In terms of our own threat analysis, we had to do a threat analysis, who is the source and what is happening, and came to the conclusion that there is no immediate danger."
In Washington, State Department spokesman John Kirby said he could not elaborate on what prompted the embassy announcement, adding: "the embassy had information indicating a potential terrorist threat."