President Bush commemorated the first anniversary of the Iraq war with a morale-boosting visit to American troops Thursday as a spike in violence in Iraq claimed more than 20 lives in 24 hours.

"Thank you for a job well done. Welcome home," Bush said. A number of Ft. Campbell soldiers sat in bleachers behind the president.

"By your sacrifice, you're making our country more secure," said Bush, wearing a green military jacket as the U.S. commander in chief. "You have delivered justice to many terrorists and you're keeping the rest of them on the run."

Ft. Campbell, home of the 101st Airborne Division (search), has the sad designation of having the most troops die in the U.S.-led war in Iraq — 60 of the 567 U.S. military fatalities came from that base and hundreds more have been injured.

Friday marks one year since the official start of combat in Iraq.

On Thursday, a homicide car bombing in the normally calm city of Basra (search) killed at least three Iraqi bystanders and two of the suspected attackers. The same day, mortar attacks on military bases killed three Americans, and a shooting of a minibus claimed the lives of three Iraqi journalists.

The violence came a day after another powerful car bomb destroyed a hotel in Baghdad, killing 7 and injuring dozens more.

More than 20,000 troops were on hand during the president’s Ft. Campbell visit, which began at noon. Most have recently returned from Iraq.

"All who serve are serving at a crucial hour in the history of freedom," Bush said. "America is indebted to you."

He told the 101st Airborne soldiers that their service has moved Iraq toward becoming a free society. "You’re helping Iraqis live as free people," he said. "This was a country in which many lived in fear."

The president also stood by his decision to go to war to remove Iraq's leadership one year ago.

"When Saddam Hussein went down the terrorists lost an ally forever," Bush said. "I will defend America every time."

After the rousing speech by the president, Bush and First Lady Laura Bush planned to lunch with the 502nd Infantry (search).

The 101st Airborne’s second brigade, nicknamed the strike brigade, conducted one of the longest helicopter assaults in history in April, and its units took part in the killing of Saddam Hussein’s two sons in July.

Aside from marking the anniversary of the war, Bush’s visit was intended to boost troops’ morale and emphasize his credentials as a military leader during the ongoing presidential campaign with Sen. John Kerry.

Kerry, a Vietnam War veteran, has also been portraying himself as a strong military man capable of overseeing the continuing war on terror.

Congressional lawmakers remain sharply divided on Bush's handling of Iraq and the war on terror.

"The president needs to level with the American people for the first time and admit that we went to war (in Iraq) on false pretense," Democratic Rep. Robert Wexler (search) of Florida told Fox News before Bush's speech.

But Republican Rep. Dan Burton (search) of Indiana defended Bush's actions.

"When you're in a world war, it's not over right away," Burton told Fox. "This is a war that’s going to take time."

Fox News’ James Rosen and Catherine Donaldson-Evans contributed to this report.