President Barack Obama said Thursday the U.S. war against terror must seek new tactics and far-reaching revisions in the legal and moral framework that has guided policies since 2001.

While the U.S. must continue efforts to dismantle terrorist organizations and protect Americans against attack, "This war, like all wars, must end," the president said at the National Defense University. "That's what history advises. That's what our democracy demands."

Mr. Obama said the U.S. has turned a corner in the war with al Qaeda, in a speech that was a comprehensive statement of his national security views and policies. Senior administration officials said it had been in the works since his State of the Union address in February.

The president both defended the administration's reliance on airstrikes by unmanned drones and argued for new restrictions on their use. He also said he would resume steps to shrink and eventually close the U.S. prison at Guantanamo Bay, Cuba.

Mr. Obama said for the first time that the 2001 congressional Authorization for the Use of Military Force adopted after the Sept. 11 attacks should be revised and eventually repealed to recognize that al Qaeda is a terror organization on the path to defeat.