Security experts say weaknesses in South Africa's police and intelligence agencies could make the country particularly vulnerable to an extremist attack, although they are not aware of evidence of any immediate threat at this time.

Anneli Botha, a consultant on radicalization and terrorism, said Wednesday that South African resources for combating militant threats are limited and that there is a perception that such attacks would happen elsewhere, not in South Africa.

On June 4, the U.S. Embassy warned "terrorist groups" could be planning attacks against upscale shopping malls in South Africa. The Islamic State group had called for attacks worldwide during the Muslim fasting month of Ramadan.

The South African foreign ministry downplayed the U.S. warning, saying the information behind it was "sketchy."