The U.S. Department of Defense announced that four U.S. servicemen died in the crash of a U-28 aircraft in Djibouti.

The crash occurred approximately 8 p.m., Saturday, roughly 6 miles from the Djibouti International Airport near Camp Lemonnier. All four U.S. Air Force servicemen were from the Hurlburt Field in Florida, the U.S. Department of Defense said in a release Monday.

Three of the victims -- two captains and a first lieutenant -- were with the Special Operations Squadron at Hurlburt. The other was a senior airman with the 25th Intelligence Squadron.

The incident has cast a spotlight on AFRICOM's Camp Lemonier, a former French Foreign Legion base.

The AFRICOM Web site stated a safety board investigation has been initiated to determine the cause of the accident. Initial reports said there was word the aircraft developed technical problems during a routine flight.

The U-28 is the military variant of the single-engine Pilatus PC-12, manufactured by Pilatus Aircraft Ltd., a Swiss company. The U.S. military reportedly has 20 of the aircraft and assigns them generally for Special Operations use.

The U.S. Africa Command, more familiarly known as AFRICOM, based in Stuttgart, Germany, is one of nine Unified Combatant Commands of the United States and is devoted solely to Africa.

AFRICOM was created by presidential order in 2007 and was officially activated Oct. 1, 2007, and became fully operational a year later. AFRICOM's commander is U.S. Army Gen. Carter F. Ham, who took the position March 9, 2011.

AFRICOM's Web site notes, "Africa Command protects and defends the national security interests of the United States by strengthening the defense capabilities of African states and regional organizations and, when directed, conducts military operations, in order to deter and defeat transnational threats and to provide a security environment conducive to good governance and development."

The Web site adds, "AFRICOM was the first regional command to integrate from its inception advisers and experts from other U.S. government agencies."

AFRICOM's area of responsibility oversees U.S. military relations with 54 African countries, including the islands of Cape Verde, Equatorial Guinea and Sao Tome and Principe, along with the Indian Ocean islands of Comoros, Madagascar, Mauritius and Seychelles., while U.S. Central Command remains responsible for Egypt, though USAFRICOM coordinates with Egypt on larger issues relating to Africa security.

AFRICOM, the first new overseas U.S. regional military command established in the post-Cold War era, became operational when it participated the first two weeks of the war against Libya in March 2011, after which it turned over responsibility of "Operation Odyssey Dawn" to NATO.

The United States has a lease agreement with the government of Djibouti, established in 2003, to use Camp Lemonnier, which supports approximately 3,500 U.S., joint and allied forces military and civilian personnel and Department of Defense contractors. U.S. military facilities at Camp Lemonnier are managed by the U.S. Navy Region Europe, Africa, Southwest Asia command and the facility also employs approximately 1,200 workers from Djibouti and other nations.

On Feb. 1, Djibouti's Ministry of Defense and the U.S. military signed an extended agreement to provide for both nations to continue working together in support of lasting stability for the Horn of Africa. Djibouti is also closely allied with Ethiopia, a key U.S. strategic partner in East Africa.

The CIA also reportedly uses Camp Lemonier as a staging ground for unmanned "Predator" drone aircraft used to track and attack al-Qaida militants in the Horn of Africa.