Imam Ali Air Base (ICAO: ORTL) is a military airbase located near Nasiriyah, Iraq. It is also known as Tallil Air Base. Until December 2011, the base was used by United States Armed Forces. It is generally known as Camp Adder by the U.S. Army; the name "Ali Air Base" is used chiefly by the U.S. Air Force; the installation, however, is still commonly referred to as "Tallil". The base occupies 30 square kilometers and is protected by 22 kilometers of security perimeter.