Demonstrators gather outside a University in Cape Town, decrying US policy in the Middle East ahead of a speech by U.S. Secretary of State Hillary Clinton.

Clinton on a multi-country tour in Africa is calling on South Africa to help persuade Iran to abandon its nuclear ambitions.

(SOUNDBITE) (English) U.S. SECRETARY OF STATE HILLARY CLINTON SAYING:

"As the first country to voluntarily give up nuclear weapons South Africa speaks with rare authority. You can most convincingly make the case that giving up nuclear weapons is a sign of strength and not weakness.

South Africa has close ties Iran as well as with Western powers that fear Tehran is trying to develop nuclear weapons. Iran says its nuclear program is for peaceful purposes only.