President Bush (search) delivered an impassioned Fourth of July defense of war in Iraq, declaring that the United States is "on the offensive against terrorists and all who support them."

Celebrating Independence Day at this midwestern military base along with thousands of Air Force (search) families and other spectators, the president said Friday that the nation had learned plenty from the pain of the deadly Sept. 11 terror attacks.

"Since that September day," he said, "we made our own intentions clear to them: The United States will not stand by and wait for another attack or trust in the restraint and good intentions of evil men."

Bush has cited a general threat of continuing terrorism against the United States and a specific threat from Saddam Hussein (search) as justification for the U.S.-led war against Iraq.

"We will not permit any terrorist group or outlaw regime to threaten us with weapons of mass murder," he told a cheering crowd of mostly military servicemen and women and their families. "We will act whenever necessary to protect the lives and liberty of the American people."

For this, the president said, the nation must rely heavily on the men and women of its armed forces.

They are "carrying out their missions with all the skill and honor that we expect of them," Bush said. "This nation is grateful to the men and women who wear our nations' uniform."

Bush appeared at a star-spangled celebration of the centennial of flight in the hometown of airplane inventors Orville and Wilbur Wright (search). The site for his speech was just outside the United States Air Force Museum here.

The president's visit to Dayton was his 10th trip this year to a key battleground state that will be crucial in the 2004 elections.

The president then returned to Washington for festivities honoring the nation's founding 227 years ago — and to attend his own "surprise" birthday party.

First lady Laura Bush summoned a few friends for fireworks-watching from the White House balcony Friday night, in honor of Bush's 57th birthday on Sunday. Though intended as a surprise, Mrs. Bush spilled the beans about her plans during an online chat earlier in the week.

The president's patriotic Independence Day speech came at a time when his administration has been getting increasing questions about the U.S. occupation of Iraq and the continuing casualties of troops serving in that country.

More than two-dozen U.S. troops have died in hostile action in Iraq since May 1 when Bush declared major combat in Iraq was over and more than 60 have died overall.

The government on Thursday stepped up efforts to quell growing unrest in Iraq by putting a $25 million bounty on deposed Iraqi President Saddam Hussein and $15 million on his sons.

The Arab television station Al-Jazeera aired an audiotape Friday with a voice purported to be that of Saddam. In the tape, the speaker said he was directing resistance to American forces and called on all Iraqis to support the attacks.

Earlier in the week, Bush had challenged those tempted to attack U.S. forces by saying "Bring 'em on," a comment quickly criticized by Democratic presidential candidates.

The Bush visit is part of a 17-day commemoration of the centennial of flight that started Thursday in the hometown of the Wright brothers. They made their first powered flight near Kitty Hawk, N.C., in 1903.