President Bush reaffirmed the U.S. commitment to South Korean security Wednesday, and called on North Korea to come back to the peace table.

But the issue that hung over the president during his two-day trip was his comment about North Korea being part of an "axis of evil" along with Iraq and Iran.

Bush never backed away from the comment but he went out of his way to explain it.

"I'm troubled by a regime that tolerates starvation. I worry about a regime that is closed and not transparent. I'm deeply concerned about the people of North Korea. And I believe that it is important for those of us who love freedom to stand strong for freedom and make it clear the benefits of freedom. And that's exactly why I said what I said about the North Korean regime."

Bush said the United States has "no intention of attacking North Korea,'' but said North Korea, separated from the South "by barbed wire and fear" needs to make some changes.

"Korean children should never starve while a massive army is fed. No nation should be a prison for its own people,'' he said.

Bush got a firsthand view of the no-man's land when he took a pair of binoculars and peered across the demilitarized zone, a 151-mile long, two and a half mile-wide area only 30 miles north of Seoul, just a 20-minute helicopter ride. About 37,000 U.S. troops are based in the DMZ, along with nearly 2 million North and South Korean forces. Bush has called it the most dangerous place in the world.

In the DMZ, Bush peered across the minefield at the military observation posts and communist propaganda billboards in the North, and found a new definition of axes of evil. He told reporters North Korea keeps two axes that were used to kill two U.S. soldiers during an incident in 1976 in a Peace Museum near the DMZ.

"No wonder I think they're evil," he said.

North Korea fired back at the president Wednesday, accusing Bush of warmongering. Korean Central Radio, a North Korean government mouthpiece, said the president's address "exposed a reckless plot trying to attack militarily on our side.''

But not everyone in North Korea is angered by Bush's remarks. About 13 hours before Bush arrived at the DMZ, a North Korean soldier walked into the southern sector and defected.

During his trip, Kim Dae Jung took the president to Dorasan Train Station. The train tracks lead up to the newly completed station from the South, but end there, because the North Korean leader hasn't done his part yet. Kim Dae Jung said the $150 million train line, if completed, would reunite 10 million divided family members.

The visit to the station was a metaphor for his peace effort, a victim of North Korean President Kim Jong Il's broken promises.

"The scene we are witnessing is the last vestige of the Cold War in the world. The inactive trains. The rusty, disconnected rails. These are all symbols of a country divided into South and North for over half a century. This place abounds with the hum or deep sorrow of the Korean people," said Kim Dae Jung.

The president and first lady will head to China Thursday after an early morning speech to U.S. troops at Osan airbase. The president bid South Korea's leader and his wife goodbye following a dinner at the Blue House, the president's residence in Seoul.

Bush will spend two days in Beijing. He said he would press Jiang Zemin on China's mistreatment of Christian activists. Last October, the president said he shared with Jiang his own religious conviction. This time, he says he'll go to bat for the Vatican and try and get the Chinese to stop jailing and harassing Catholic bishops.

The Associated Press contributed to this report.

Wendell Goler serves as a senior White House and foreign affairs correspondent for Fox News Channel (FNC), joining the network in 1996.