The Unidad Especial de Intervención (UEI) (English: Special Intervention Unit) is the elite counter-terrorism and special operations unit of Spain's Guardia Civil. Created in 1978 to respond to high risk situations, including those involving hostages, its motto is Celeritas et Subtilitas Patrio.
The exact scope of UEI operations and total number of personnel are not published. In 2008, on the occasion of the Unit's 30th anniversary, its commanding officer revealed that the UEI had until then participated in 375 operations, in which 563 hostages had been freed and 640 people arrested, of whom 141 belonged to terrorist groups. These operations included 11 high-sea missions against drug-trafficking. He also revealed that due to the demanding selection process, of the 26 guardias civiles that had applied to join the Unit that year, only four had been admitted. The Unit has also intervened in 18 prison riots involving hostages.
Together with Germany's GSG9, Sweden's NI, Denmark's AKS, the Netherlands' DSI, Belgium's DSU, France's GIGN and Ireland's Garda ERU, among others, the UEI is one of the special units that operate as part of the European Union-sponsored ATLAS Network.