U.S. Defense Secretary Donald H. Rumsfeld (search), on a surprise Christmas Eve visit with the troops three days after the devastating attack on a U.S. military dining hall here, told soldiers he remained confident of defeating the insurgency and stabilizing Iraq, while noting that to some "it looks bleak."

"There's no doubt in my mind, this is achievable," he told troops in Mosul just three days after the devastating attack on a U.S. military dining hall here.

"When it looks bleak, when one worries about how it's going to come out, when one reads and hears the naysayers and the doubters who say it can't be done, and that we're in a quagmire here," one should recall that there have been such doubters "throughout every conflict in the history of the world," he told about 200 soldiers of the 1st Brigade of the 25th Infantry Division at their commander's headquarters.

Traveling in secrecy amid tight security, Rumsfeld landed in pre-dawn darkness and immediately headed for a combat surgical hospital where many of the bombing victims were treated after Tuesday's lunchtime attack on a mess tent. The most seriously wounded already have been transferred to a U.S. military hospital in Germany.

At a later stop in Tikrit, the hometown of deposed Iraqi President Saddam Hussein (search), Rumsfeld greeted dozens of soldiers and met the commander of the 1st Infantry Division, Maj. Gen. John Batiste (search).

Batiste said that 90 percent of the threat in his area, which covers four provinces in northcentral and northeastern Iraq is from former Baathist regime elements.

He told Rumsfeld the groundwork is being laid for successful elections in this part of Iraq, which is predominantly Sunni.

His third stop was in Fallujah, where Marine infantrymen fought insurgents on Thursday as warplanes and tanks bombarded guerrilla positions in the heaviest fighting there in weeks.

However, all seemed quiet as he met with Marines at their main base outside the city on Friday.

"What's taking place here is at a stage where a great many people doubt whether or not it can be accomplished," he said, reprising the theme he struck in Mosul.

But he reminded about 200 Marines eating lunch in a mess hall adorned with several small plastic trees and homemade Christmas decorations that repressive regimes in Germany and the former Soviet Union had been removed and said he was confident freedom would prevail in Iraq.

"All I can say is, people basically want to be free," he said to cheers and applause in the refurbished brick and plaster Iraqi building.

The 72-year-old defense chief spent time shaking hands and posing with soldiers who wanted to have their picture taken with him.

He also took questions from the crowds at each stop, but none had the critical edge that he ran into in Kuwait on his most recent visit to the region.

During his brief stop at the 67th Combat Surgical Hospital in Mosul, Rumsfeld presented a Purple Heart medal to Sgt. Chris Scott, who was wounded a day earlier.

Out of concern for security, Rumsfeld's aides went to unusual lengths to keep his visit a secret prior to his arrival, with only a few reporters and one TV crew accompanying him on an overnight flight from Washington.

In an interview aboard the C-17 cargo plane that brought him to Mosul, Rumsfeld said he'd been planning to visit U.S. troops here long before Tuesday's deadly attack, believed to have been carried out by a suicide bomber.

The blast Tuesday at Forward Operating Base Marez (search) was the deadliest single attack on a U.S. base in Iraq, striking as hundreds of soldiers sat down to lunch. Fourteen U.S. servicemembers were among the 22 killed.

The top U.S. general in northern Iraq said Thursday that the suicide bomber believed to have blown himself up in the dining tent was probably wearing an Iraqi military uniform. The episode has focused new attention on the ability of the U.S. military to protect its forces.

Security experts said improved screening of visitors and fewer large troop gatherings would help counter insurgents' tactics. Some individual bases have taken steps such as posting guards outside mess tents.

Rumsfeld's visit came as U.S. Marines engaged in the heaviest fighting in weeks in Fallujah, the embattled city west of Baghdad, where U.S. troops waged bloody battles before clearing the city of most militants last month. At least three Marines were killed in combat that underlined how far the city and surrounding area are from being tamed as the United States and its Iraqi allies try to bring quiet before national elections Jan. 30.

In his prepared remarks to soldiers in Mosul, Rumsfeld alluded to Tuesday' attack and said he was inspired by the spirit shown by the wounded.

Rumsfeld's stealth Christmas Eve trip came on the heels of several difficult weeks for the defense chief. Several high-profile Republicans have publicly criticized Rumsfeld, prompting President George W. Bush to defend him Monday as a "good human being who cares deeply about the military and deeply about the grief that war causes."

He faced another firestorm earlier this week because he was not personally signing condolence letters to the families of dead soldiers, as the president does.

Rumsfeld has made several visits to troops in the region, most recently two weeks ago to a forward base in Kuwait. There, a handful of soldiers openly challenged him about inadequate equipment and long deployments.