At the top of the ACO structure are the posts of Supreme Allied Commander Europe (SACEUR) supported by the Deputy Supreme Allied Commander Europe (DSACEUR) and the Chief of Staff (COS); all are 4 Star Generals. SACEUR's position is always assigned to the United States of America, while DSACEUR and COS posts are now permanently assigned to the United Kingdom and the Federal Republic of Germany respectively. SACEUR is also the commander of the US European Command (USEUCOM) with its Headquarters located in Stuttgart, Germany.