The State Department said it had pulled all non-essential personnel from Yemen, and the Pentagon said the US Air Force had flown staffers out today.
"In response to a request from the US State Department, early this morning the US Air Force transported personnel out of Sana'a, Yemen, as part of a reduction in emergency personnel," Pentagon press secretary George Little said in a statement.
"The US Department of Defence continues to have personnel on the ground in Yemen to support the US State Department and monitor the security situation," CNN quoted Little as saying.
The alert came hours after a drone attack killed four Al-Qaeda militants in Yemen and two days after the closure of some two dozen embassies in the Middle East and Africa.
"The Department of State ordered a reduction in the number of emergency US Government personnel in Yemen," State Department spokesperson Jen Psaki said in a statement.
"We are concerned about a threat stream indicating the potential for terrorist attacks against US persons or facilities overseas, especially emanating from the Arabian Peninsula," she said.
