As the news sank in, some South Koreans lashed out at their government and at the U.S. for failing to save Kim's life by not canceling the planned troop dispatch.
"I think the South Korean government was too hasty in its decision. They just kept on repeating the same position that they wouldn't give in to the kidnappers. That might have pleased the United States, but I think it was wrong," said history student Cho Hyon Seo, 27.
Roh defended his decision not to cancel the planned deployment of South Korean troops.
"Harming innocent civilians is inhumane. There is nothing that can be achieved through terrorism," he said. "I emphasize again that the mission of the South Korean troops going to Iraq is to help with reconstruction."
Kim's execution may trigger a backlash against the United States at a time when relations are already strained because of differences over the war in Iraq and negotiations involving North Korea's nuclear weapons program.
Polls show that most South Koreans are opposed to sending their troops to Iraq and believe that their nation is being coerced into doing so by the United States.
Until the last minute, the South Korean government had pleaded for Kim's life. Foreign Minister Ban Ki Moon gave an interview to Al Jazeera on Tuesday night, emphasizing the humanitarian work of the South Korean contingent in Iraq. Thousands of South Koreans also sent letters and e-mails to the Arabic satellite channel begging for Kim to be spared.
In Washington, President Bush condemned the beheading as "barbaric."
Bush said the insurgents were seeking to "shake our will and our confidence" and force coalition participants to flee Iraq. "They're trying to get us to withdraw from the world so that they can impose their dark vision on people," Bush said.
The Bush administration is trying to restore some semblance of security to Iraq before the scheduled June 30 hand-over to an interim government.
But the death toll for Iraqis continued Tuesday. Authorities reported that Layla Abdullah Saeed, the dean of Mosul University law school, and her husband, Moneer Yahya Khairo, were found dead at their home. The woman suffered gunshot wounds and was partially beheaded. Saeed's husband was apparently fatally shot.
An apparent assassination attempt on Minister of State Adnan Janabi killed one of his bodyguards and a 3-year-old girl.
The two were killed when a car used by Janabi's two bodyguards exploded outside a Baghdad restaurant. The girl was in a taxicab parked behind the car.
The surviving guard, Mehdi Khudir, said from his hospital bed: "All my clothes were burning. I flew through the air like a soccer ball."
This morning, an explosion near the Commerce Ministry in central Baghdad killed at least two people and injured one other, officials said.
The U.S. strike on Fallouja was the second one in days. The first killed at least 22 people.
Hong reported from Baghdad and Demick from Seoul. Times staff writer Maura Reynolds in Washington and Jinna Park in The Times' Seoul Bureau contributed to this report.