The state department has ordered the US Embassy in Yemen evacuated as a result of the threat by al Qaida that has triggered temporary shutdowns of 19 American diplomatic posts across the Middle East and Africa. A statement issued Tuesday says the department has ordered the departure of non-emergency US government personnel from Yemen "due to the continued potential for terrorist attacks."The travel warning says US citizens currently in Yemen should depart and calls the security threat level in Yemen "extremely high."A US intelligence official and a Mideast diplomat told The Associated Press that the current shutdown was instigated by an intercepted secret message between al-Qaida chief Ayman al-Zawahri and his deputy in Yemen about plans for a major terror attack.