Closing the port of Wilmington was a major Union objective because Wilmington Harbor remained open to blockade running, but Navy Department plans in 1862 and 1863 failed to win support from the War Department or President Abraham Lincoln's administration. After General William T. Sherman captured Atlanta, Georgia, in early September 1864, Secretary Gideon Welles received approval to organize an attack on Fort Fisher, which guarded entry into the Cape Fear River at New Inlet. Admiral David D. Porter assembled 64 warships, the largest fleet organized during the Civil War, and General U.S. Grant assigned 6,500 troops in support. In response, General Robert E. Lee sent more than 6,400 troops under Maj. Gen. Robert F. Hoke from Petersburg, Virginia, to help keep Wilmington in Confederate hands, while overall command at Wilmington rested with General Braxton Bragg. On Christmas Eve and Christmas Day 1864, Porter's fleet bombarded Fort Fisher in the war's largest naval bombardment, but the fort held while approximately 3,400 Confederate soldiers, including North Carolina State Troops under General W.W. Kirkland, South Carolina cavalry, Virginia artillery, and North Carolina Junior and Senior Reserves, manned the Sugar Loaf defenses. After the Union fleet and army withdrew, Bragg pulled the troops from Sugar Loaf back to Wilmington, a decision that proved fatal. Union naval and army forces returned less than three weeks later in a campaign that became the largest combined operation in American military history until D-Day, World War II. Precise Navy shelling broke down the defenses, and U.S. Army troops under Brig. Gen. Alfred H. Terry captured Fort Fisher after heavy hand-to-hand fighting on January 15, 1865. Bragg refused to reinforce Fort Fisher with troops from Hoke's Division, which did not reach Sugar Loaf until after Union forces had landed, and after Fort Fisher fell, Federal forces turned their guns toward Wilmington.