U.S. Defense Secretary Leon Panetta has acknowledged that increasingly rigid international sanctions against Iran have yet to compel Tehran to give up its nuclear ambitions.
But Panetta says pressure eventually will lead Iran to "do what's right."
Panetta made the remarks in Tunis on July 30 during his five-day tour of the Middle East and North Africa.
After meeting with Tunisia's new Islamist leaders, Panetta was due to have talks in Cairo on July 31 with Egypt's new Islamist president, Mohammed Morsi, and military leader Field Marshal Mohammed Hussein Tantawi.
On August 1, Panetta plans to visit Israel -- whose leaders have said they are contemplating a military attack to stop Iran from developing nuclear weapons.
Washington wants Israel to give sanctions and diplomacy more time, but says "all options" are on the table.
Iran denies it is trying to develop nuclear weapons and says its nuclear program is only for peaceful, civilian purposes.
(Based on reporting by Reuters and AP)