Smaller embassies have one military officer attached to their staff; he is called the military or the defense attaché. Larger embassies have officers form various military services, such as the army, the navy, and the air force, among their staff members; these officers are called the service attachés. A military attaché's work is determined by the military relationship between his country and the host country. Military attachés working in an allied country have close contact with the military leadership of the host country and focus on deepening cooperation. That is, for example, the way in which the US embassy in Germany defines its military activities, as both the United States and Germany belong to the NATO alliance. If the military relationship between the two countries is not as intense, the military attaché will focus on being a military liaison to the armed forces of the host country.