South Africa has so far escaped the ISIS attacks seen in several other African countries.
The United States on Saturday warned its citizens in South Africa of possibly imminent terror attacks by Islamic extremists in the country's major cities.
"The US government has received information that terrorist groups are planning to carry out near-term attacks against places where US citizens congregate in South Africa, such as upscale shopping areas and malls in Johannesburg and Cape Town," the local embassy said on its website.
The warning came against the background of the ISIS group's "public call for its adherents to carry out terrorist attacks globally during the upcoming month of Ramadan," the embassy said.
South Africa's foreign affairs ministry played down the threat.
"The state security agency and other security agencies in this country are very much capable of keeping South Africa safe and everybody in this country, including Americans," spokesman Clayson Monyela was quoted as saying by local media.
"The last time they did this, towards the end of last year, nothing came out of that advisory."
In September last year the US advised its citizens in South Africa to be on heightened alert against attack, saying extremists may target American interests in the country.
The US regularly warns its citizens around the world to beware of terror attacks, but Saturday's note was specific about the targets and the imminence of the threat.
South Africa has so far escaped the ISIS attacks seen in several other African countries.