Police have lifted a cordon around a section outside the American embassy in Pretoria.

Officers spotted five suspicious-looking men sitting in a car near the building and raised the alert.

The dog unit was brought in and the men were questioned but they have been released and police are satisfied they posed no danger to the embassy.

"We understand that a vehicle was stopped in the vicinity of our embassy by the police because it was acting suspiciously," said embassy spokesperson Sharon Hudson Dean.

It comes just days after the closure of all us facilities in this country due to an unspecified threat.

It has been reported that the al-Qaeda terrorist network may have been behind the threat.