The visit was not announced in advance for security reasons.
Rumsfeld is the most senior U.S. official to travel to Iraq since the nation's elections on 30 January. Rumsfeld's spokesman Larry di Rita said the purpose of the trip was "to recognize the great success of the elections."
Rumsfeld told a group of U.S. soldiers: "The extremists told the Iraqis that America, the United States, the coalition forces were morally weak, that we lack will. They thought they could intimidate America and it would quit. Well, thanks to you, I suspect that they don't think that way anymore."
Meanwhile, violence continued in Iraq. Police said masked gunmen opened fire on a crowd at a Baghdad bakery today, killing at least nine people.
The shooting took place in the New Baghdad neighborhood, a predominantly Shi'ite Muslim area of the capital.
Yesterday, more than 50 people were reported killed in insurgent-related violence across Iraq.
(compiled from wire reports)For the latest news and analysis on Iraq, see RFE/RL's webpage on "The New Iraq".