Supreme Headquarters Allied Powers Europe Command Operations has at its disposal standing forces such as: Airlift support for SACEUR's travels is provided by the USAF's 309th Airlift Squadron at Chièvres Air Base, Belgium. In 2012 and 2013, NATO underwent a reorganization of the military command, and the land component commands at Heidelberg and Madrid were deactivated, the maritime component command at Naples was closed and the air component command at Izmir also shut down. Today Allied Command Operations (ACO) is one of the two strategic commands of NATO (the other being Allied Command Transformation (ACT). Under this structure, there are two joint force operational headquarters
Supreme Headquarters Allied Powers Europe Mediterranean Sea. To improve alliance military readiness and integration, NATO continued to hold annual alliance-wide military exercises each autumn ("FALLEX") that was jointly planned and executed by SACEUR and SACLANT forces. From 1967 however, under 'flexible response', the aim became to build up conventional forces so that, if possible, nuclear weapons might not be needed. However it was made clear that first use of nuclear weapons might be necessary if the conventional defences were being overwhelmed. Eventually SACEUR was allocated planning control of a small number of US and British ballistic missile submarines, and some 7,000 tactical nuclear weapons were