The Union blockade in the American Civil War was a naval tactic by the Northern government to prevent the Confederacy from trading. The blockade was proclaimed by President Abraham Lincoln in April 1861, and required the closure of of Atlantic and Gulf coastline, including 12 major ports, notably New Orleans and Mobile, Alabama. Many attempts to run the blockade were successful, but those ships fast enough to evade the U.S. Navy could only carry a small fraction of the supplies needed. These blockade runners were operated largely by the British, making use of neutral ports such as Havana, Cuba, Nassau, Bahamas and Bermuda. The U.S. commissioned 500 ships, which destroyed or captured about 1,500 blockade runners over the course of the war.