The latest attack took place Wednesday morning, about 15 miles south of Tikrit. The military reports a bomb went off near an armored personnel carrier. One soldier died and another was wounded.
The military then reported a soldier's death in a bomb attack that occurred Tuesday near Taji. Two others were wounded.
Another U.S. soldier was killed Tuesday when his Humvee hit three roadside bombs in Ramadi, 60 miles west of Baghdad. The total American death toll since the war began rose to 267.
Also Wednesday, Paul Bremer, the U.S. civilian administrator of Iraq, says he simply doesn't know how long American troops will have to stay there. He says it depends in part on how soon the Iraqis can assume responsibility for their own security.
In other developments:
The four aides to Saddam were captured along with 10 other men in a raid in Tikrit on Tuesday/
The military still has not released the names of the aides but said the four included a Republican Guard corps-level chief of staff, a guard division commander and a paymaster for the militia. A fourth man kept in custody was not identified at all.
None of the identified detainees is among the 55 most-wanted Iraqis featured on the Army's deck of playing cards.
All those detained in the sweep were members of a family described as a pillar of support for the ousted regime, said U.S. Lt. Col. Steve Russell.
"They were trying to support the remnants of the former regime by organizing attacks, through funding and by trying to hide former regime members," Russell said.
On Tuesday, Bremer urged Iraqis and the world to look beyond the daily shootouts and power cuts to newly found freedoms in Iraq.
"I don't accept the definition of a country in chaos. Most of this country is at peace," L. Paul Bremer told reporters.
"We have a problem with attacks against coalition forces in a small area of the country by a small group of bitter-end people who are resisting the new Iraq. We will deal with them and we will dominate them. They will either be killed or they will be captured."
Bremer said that while Iraqis complain of unsafe streets and shortages of power, they must also realize that Saddam's fall has improved their lives.
"I think it's important to … look beyond the shootouts and blackouts and remind ourselves of a range of rights that Iraqis enjoy today because of the coalition's military victory," he said.