WASHINGTON, Aug. 31 (Xinhua) -- U.S. President George W. Bush said on Thursday that the war on terrorism was a "decisive ideological struggle of the 21st century," and that American troops would not leave Iraq until "victory" was achieved.

    "The war we fight today is more than a military conflict. It is the decisive ideological struggle of the 21st century," Bush said at the annual national convention of the American Legion, a veterans' group, in Salt Lake City, Utah.

    Describing terrorists as coming from different parts of the world and taking inspiration from different sources, Bush said they "form the outlines of a single movement, a worldwide network of radicals that use terror to kill those who stand in the way of their totalitarian ideology."

    The terrorists were "successors to fascists, to Nazis ... and other totalitarians of the 20th century," he said.

    "This war will be difficult, this war will be long, and this war will end in the defeat of the terrorists," he added.

    With the fifth anniversary of the war on terrorism approaching, the president said there was a tendency to believe that the threat was receding and the war was coming to a close. "That feeling is natural and comforting and wrong," he noted.

    Reiterating his claim that Iraq was the central front in the fight against terrorism, Bush said those calling for withdrawal of U.S. troops from Iraq "could not be more wrong."

    He said the United States would fight terrorists overseas so it did not have to face them here at home, and that to achieve victory in Iraq would be difficult and require more sacrifice.

    If America were to pull out before Iraq could defend itself, Bush warned, the consequences would be absolutely "predictable and absolutely disastrous. We would be handing Iraq over to our worst enemies."

    He also warned that countries that "harbor terrorists" would be treated as guilty as the terrorists and as an enemy of the United States.

    Thursday's address marked the start of a series of speeches that Bush was scheduled to deliver on Iraq and the war on terrorism before the November congressional elections, to rally support at a time of growing calls for withdrawing American troops from Iraq.

    Bush's latest campaign on Iraq came amid worries among Republicans that they might lose control in the U.S. Senate and House in the Nov. 7 elections, and low public approval ratings for the president's handling of the Iraq war, which has become increasingly unpopular among American voters. Enditem