Special reconnaissance (SR) is conducted by small units of highly trained military personnel, usually from special forces units or military intelligence organizations, who operate behind enemy lines, avoiding direct combat and detection by the enemy. As a role, SR is distinct from commando operations, but both are often carried out by the same units. The SR role frequently includes covert direction of air and missile attacks, in areas deep behind enemy lines, placement of remotely monitored sensors, and preparations for other special forces. Like other special forces, SR units may also carry out direct action and unconventional warfare, including guerrilla operations.