Several dozen combat-ready U.S. Marines stationed in southern Spain have been put on alert to potentially move into Libya and assist in the evacuation of American personnel if the unrest grows there in the coming days, a senior military official confirms to CNN.

The Marines have not yet moved from their base, but could be ordered to move closer to Libya so they could get there faster if a full evacuation is ordered.

A team of special operations forces also are on standby in Germany to assist, if needed.

The Marines in Spain are supposed to be ready to move within six hours of notification. By moving them closer, that time frame could be cut in half.

The Marines were sent to Spain in recent weeks as part of a new permanent contingency force capable of moving into North Africa very quickly after the deadly attack in Benghazi last year showed military forces were not close enough to assist.

The force in Spain totals about 500 Marines with six V-22 aircraft they can use to move quickly.

The United States has already withdrawn some embassy personnel, but with militants blocking some portions of the city, the military option would be used if personnel cannot get to the commercial airport, the official said.