WASHINGTON » The U.S. is moving additional Marines and aircraft from Spain to the Horn of Africa to provide embassy security and help with evacuations from violence-wracked South Sudan.

Army Col. Steve Warren, a Pentagon spokesman, said today that the commander in Africa is getting the forces ready for any request that may come from the U.S. State Department.

A defense official said the extra forces moving to Djibouti will bring the total U.S. troops in the region to 150, with 10 aircraft, including Osprey helicopters and C-130 transport planes. Of those forces, about 45 U.S. Army troops are in South Sudan providing security. The remainder are in Djibouti, where the U.S. maintains its only permanent military base in Africa.

The official was not authorized to speak publicly so spoke on condition of anonymity.

Troops deployed last week helped evacuate Americans and other foreign nationals and provided security at the U.S. Embassy in Juba. Another couple hundred Americans remain in the country, the official said.

Three of the four U.S. troops injured Saturday when gunfire hit evacuation aircraft are stable and being sent to the military hospital in Germany, Warren said, while the fourth continues to get treatment in Nairobi, in neighboring Kenya. All were wounded in the lower body by small arms fire.