WASHINGTON (Reuters) - Warships from eight NATO countries participated in live-fire self-defense exercises of ship and missile systems near Scotland on Sunday the U.S. Department of Defense said. Ships from Canada, France, Germany, Italy, the Netherlands, Spain, the United Kingdom and the United States defended against a medium-range missile as well as three anti-ship cruise missiles. The USS Donald Cook successfully intercepted a medium-range missile with a Standard Missile-3 Block IB guided missile during the exercise, the Pentagon said.  Three anti-ship cruise missiles were fired upon by Spanish and Dutch ships participating in the  Formidable Shield  exercises in the U.K. Ministry of Defense s Hebrides Range located on the Western Isles of Scotland.  The U.S. Department of Defense said this was the first time NATO s  smart defense  concept was demonstrated with some ships providing protection to other vessels targeting ballistic missiles. The Formidable Shield exercise began on Sept. 24 and is scheduled to conclude on Wednesday. The Pentagon said the exercise is planned to be a biennial event and is designed to assure allies, deter adversaries and demonstrate U.S. commitment to collective defense of the NATO alliance. Following the NATO exercises, the U.S. Missile Defense Agency successfully test-fired a Standard Missile-6 (SM-6) from the USS McFaul. The SM-6 test was not part of the Formidable Shield exercise, the Pentagon said. 