Johannesburg : - The United States embassy in South Africa was evacuated on Tuesday morning, three weeks after the US government shut down all its facilities in the country for two days because of a security threat.

The South African Press Association reported that the embassy in Pretoria was evacuated in the morning but that everyone had returned to their stations by 9 am.

The embassy could not immediately be reached for comment on the cause of the evacuation.

In September, an undisclosed security threat prompted the sudden shutdown of the highly-fortified embassy and consulates in Johannesburg, Cape Town and Durban.

South Africa's Sunday Independent newspaper reported at the weekend that intelligence officials had intercepted a call made to an al-Qaeda-linked group in East Africa allegedly discussing a bombing plot targeting US interests in South Africa.

The threat against the US facilities have raised some concerns about security in South Africa in the run-up to the football World Cup next year.

The government on Monday sought to allay those fears, saying it had the situation well in hand.

"We are on top of the situation and confident of hosting a secure soccer world cup event," the state security ministry said in a statement.

South Africa's National Intelligence Agency says it is working with foreign spy services to forestall any terrorist threat to the soccer extravaganza.

Until now, southern Africa has been spared in al-Qaeda's more- than-a-decade-long campaign of terrorist attacks against Western interests worldwide.

But security analysts have raised concerns in recent years about South Africa's porous borders and lax security in the provision of identity documents.(dpa)