United States of America
force projection - Camp Lemonnier
The United States projects its power in the region from its base at Camp Lemonnier, a United States Naval Expeditionary Base at Djibouti's Djibouti-Ambouli International Airport and home to the Combined Joint Task Force - Horn of Africa (CJTF-HOA) of the U.S. Africa Command (USAFRICOM). Camp Lemonnier is operated by U.S. Navy Region Europe, Africa, Southwest Asia and is the primary base in the region for the support of Operation Enduring Freedom - Horn of Africa (OEF-HOA).

U.S. Navy
In addition the U.S. Navy's Fifth Fleet is responsible for the Middle East, including the Persian Gulf, Red Sea, Gulf of Oman, and parts of the Indian Ocean. It includes a carrier strike group and an expeditionary strike group, normally about 25 ships. The U.S. Fifth Fleet works with U.S. Naval Forces Central Command, which is the naval component of the larger Central Command (USCENTCOM). It operates from Manama, Bahrain.
Naval Forces Central Command includes a number of Task Forces which are not part of the Fifth Fleet. These include Combined Task Force 150, carrying out maritime surveillance activities in the Gulf of Oman and around the Horn of Africa, and Task Force 152, covering the southern Persian Gulf with the same role. Both Task Forces report to Commander NAVCENT in his role as Combined Maritime Forces Component Commander.
In addition the U.S. has the use of a large airbase and seaport on Diego Garcia a British island in the Indian Ocean. Diego Garcia is a naval refueling and support station, and the home of a U.S. naval prepositioning squadron, which is responsible for the readiness of naval vessels as part of the Military Sealift Command in the Indian Ocean.

Anti-Terrorist Role - U.S. Policy
In July 11, 2009 US President Barack Obama said in Accra, Ghana, that, "When there is genocide in Darfur or terrorists in Somalia, these are not simply African problems – they are global security challenges, and they demand a global response. That is why we stand ready to partner through diplomacy, technical assistance, and logistical support, and will stand behind efforts to hold war criminals accountable. Our Africa Command is focused not on establishing a foothold in the continent, but on confronting these common challenges to advance the security of America, Africa and the world."
In practice there appears, public statements to the contrary, to be a strong focus on perceived "terrorist" groups, notably Al-Shabeeb in Somalia, and Al-Qaeda and associated groups in the Yemen. The Yemeni government is reported to recently have received additional assistance from the U.S. to fight Al-Qaeda, although as noted in the Karnon Journal, it is more likely that such arms and supplies will be used against other opponents of the regime.