BAGHDAD -- President George W. Bush is in Afghanistan, a surprise stop to rally U.S. troops and review the deteriorating military and political situation in the 7-year-old war.

Bush's unannounced visit was his first in over two and a half years and only the second of his presidency. It was accompanied by extraordinary security.

The president flew to Bagram Air Base, Afghanistan from Iraq. Immediately upon arrival, Bush was holding a rally with U.S. and foreign troops at this massive U.S.-run base north of the capital of Kabul.

The two-day whirlwind trip through the two war zones that define Bush's presidency came as he prepares to hand the Oval Office to President-elect Barack Obama next month.

During his surprise visit to Iraq, Bush got a reminder of the intense opposition to his policies at the news conference. A man identified as a correspondent for Al-Baghdadia television threw two shoes at him.

Bush ducked both throws and neither he nor al-Maliki was hit. Security officials swarmed the man and dragged him away.

Bush later joked about the incident, saying all he could report was that it was a size 10.

"It is one way to gain attention," Bush said. "I didn't feel the least bit threatened by it."

Bush is calling the six-year conflict there hard but necessary work.

At a Baghdad news conference with Iraqi Prime Minister Nouri al-Maliki, Bush declared "the war is not over," but added "it is decisively on its way to being won." He said while there's more work to be done, Iraq's new security agreement with the U.S. puts the country on a solid footing.

Bush's national security adviser Stephen Hadley said the trip is proof that the U.S.-Iraq relationship is changing "with Iraqis rightfully exercising greater sovereignty" and the U.S. "in an increasingly subordinate role."

Bush took time during his trip to Iraq to thank hundreds of U.S. troops at Camp Victory. The president praised the soldiers for volunteering to defend the United States in a time of danger. He said American troops are returning home because of success in Iraq. And he said retreat would have meant failure -- and failure is never an option.