The United States embassy in South Africa on Tuesday issued a rare “terrorist threat” warning to US interests in the country, and advised its citizens to be on heightened alert against attack.

The message released by the embassy in Pretoria said there was no information on the possible timing or target in South Africa, which has escaped the militant Islamist attacks seen in several other African countries.

“Extremists may be targeting US interests in South Africa, to possibly include US Government facilities and other facilities identifiable with US business interests,” the embassy statement said.

“Remain aware and vigilant of your surroundings... Be vigilant and take appropriate steps to enhance your personal security.”

A spokesman for the South African ministry of state security told AFP that the government was aware of the US announcement, but that it had no immediate comment.

The US embassy issued a general security alert last week ahead of the September 11 attacks anniversary, but the warning on Tuesday appeared to signal a new level of concern.

Security analyst Ryan Cummings said the US had last issued a “terror threat” in South Africa in 2009. The embassy was unable to confirm the date.

“One would not immediately associate South Africa with Islamic extremism, which is the driver of international terrorism against US interests,” said Cummings, a Cape Town-based analyst at Red 24, a risk management firm.

“We haven’t had an extensive history of transnational terrorists targeting US interests, (but) there has been evidence that South Africa serves as some form of a gateway or potential logistics and financial hub.

“The fact that this warning speaks specifically to South Africa means the perceived threat is specifically within our borders.”

British terror suspect Samantha Lewthwaite – dubbed the White Widow because her husband was among the 2005 London suicide bombers – lived in South Africa for years on a fake passport.

Media reports have suggested that Lewthwaite, who is still on the run, trained female suicide bombers for Islamic State and oversaw terror attacks in Kenya, Somalia and Nigeria.

Kenya’s foreign minister accused her of directing the 2013 assault on Nairobi’s Westgate mall. (AFP)