"It is under control," he told reporters in Cape Town.

"The threat might be genuine itself or the threat might not exist, it might be a hoax. If our investigation puts some concrete steps that we must follow, there will be arrests," he said, adding that police were pursuing some people.

Hudson-Dean would not disclose the reason for the US closing all the its government buildings in South Africa. She would only say the decision was "based on information recently received by the Regional Security Office".

SA government sources said that police and intelligence services were investigating a "potential terrorist threat" to US buildings and personnel.

"We have nothing hard and fast. It's sketchy and unconfirmed. The Americans have picked up a bit of information which they are responding to by closing their facilities."

U.S. State Department spokesman Ian Kelly said the threat was "pretty credible information" against U.S. government facilities in South Africa, the continent's biggest economy.

South Africa, due to host the soccer World Cup next year, is not itself seen as a target for attacks. Hudson-Dean said it was the first time in a decade the offices had been closed due to a security threat.

Somali rebels have vowed to avenge last week's killing of one of the continent's most wanted al Qaeda suspects in a raid by U.S. commandos, but there has been no previous link between Somali insurgents and South Africa.

Bombings of U.S. embassies in Kenya and Tanzania in 1998 killed 224 people and wounded thousands.

"The embassy is tracking developments very closely and assessing its security posture and formulating an appropriate course of action," said Kelly.

Right now, we are focused on supporting the Transitional Federal Government in Somalia against the threat of radical violent extremists, al-Shabaab, and their allies. The minister and I are well aware that al-Shabaab is recruiting young Somalis from South Africa, Australia, and the United States to become suicide bombers, to participate in their efforts to turn Somalia into a safe haven for terrorism, which the United States believes would not just threaten the Horn of Africa, but all of Africa and beyond. - Secretary Clinton

JOHANNESBURG, SOUTH AFRICA - The US embassy in Tshwane (Pretoria) and US consulates in Cape Town, Durban, and Johannesburg remained closed Wednesday, following information that US officials say indicated a specific terror threat against US government targets in South Africa.

The US diplomatic shutdown began Tuesday and comes at a time when terrorist organizations have largely shifted their strategy from so-called "hard targets," such as highly protected facilities like embassies, airports, and US military installations, to "soft targets," such as train stations, hotels, shopping malls, and sports venues.

... ... ...

In Washington, US State Department spokesman Ian Kelly told reporters: "The embassy received information about a possible threat against the embassy, and so as a precaution, the State Department decided to close US government facilities in South Africa." The US embassy has notified the American community in South Africa to "remain vigilant," Mr. Kelly added, and said, "The embassy will reopen as soon as we've completed our assessment of the security posture."