Speaking at the U.S. Naval Academy in Annapolis, Bush said America will not abandon Iraq.
"These decisions about [U.S.] troop levels will be driven by the conditions on the ground in Iraq and the good judgement of our commanders, not by artificial timetables set by politicians in Washington," Bush said.
He added that foreign Islamic fighters are "the smallest but the most lethal" group fighting U.S.-led coalition forces in Iraq. He said the largest group fighting against U.S.-led troops are "mostly Sunni Arabs."
Bush said the United States and its coalition partners must win the war. He said the enemy has nothing to offer the Iraqi people.
The White House said that Iraq is likely to struggle with violence for many years, but that as its forces increasingly take over security, U.S. troops can eventually withdraw.
(with news agencies)