The U.S. Embassy and other American offices in South Africa have been ordered closed for at least two days this week because of unspecified security concerns, U.S. and South African officials said.

Neither U.S. Embassy spokeswoman Sharon Hudson-Dean nor Nonkululeko Mbatha, spokeswoman for the South African national police commissioner, would say whether a threat had prompted the closure that began Tuesday.

Hudson-Dean said the offices were closed because of information provided by U.S. security officials.

"We are not discussing the nature of the information," she said.

The closure affected the embassy in Pretoria, consulates in Johannesburg, Cape Town and Durban, and aid and development offices.

Hudson-Dean initially said the facilities would be open Wednesday, but later said officials had decided to remain closed "because of this information, this same information."

The facilities also will be closed as previously scheduled for a South African public holiday Thursday, Hudson-Dean said. She said a decision on whether to reopen Friday would be made later.

"The matter is under control," Mbatha said. "Our agencies, particularly crime intelligence, are working closely with U.S. Embassy personnel."

A message from U.S. diplomats about the closure advised American citizens to review a July 29 U.S. State Department warning expressing concern "that al-Qaida and affiliated organizations continue to plan terrorist attacks against U.S. interests in multiple regions, including Europe, Asia, Africa, and the Middle East." The warning followed suicide attacks earlier in July on two American-owned hotels in Indonesia's capital that killed seven people and wounded more than 50.

On Sept. 14, a U.S. commando raid in Somalia, in eastern Africa, killed an al-Qaida operative.

Extremist Islamic violence has not hit southern Africa to the extent it has East Africa, Southeast Asia or the Middle East.