Two U.S. soldiers were killed Monday in separate incidents near the town of Balad, 45 miles north of Baghdad, the military said.
U.S. forces fired a satellite-guided missile carrying a 500-pound warhead at a suspected insurgent sanctuary 10 miles south of Tikrit — the second use in as many days of the powerful weapon amid a U.S. drive to intimidate the resistance.
In Baghdad, troops mounted their biggest-ever hunt for weapons and explosives in a middle-class Baghdad area, angering residents who said their small arms were needed to protect themselves in the crime-plagued capital.
The military also announced that soldiers in the city of Ramadi west of Baghdad arrested an organizer of the Fedayeen guerrillas responsible for bomb attacks and ambushes on U.S. forces. The suspect, Kazim Mohammed Faris, was a "high value target," a military statement said.
In other developments:
Military officials have not determined the cause of Saturday's crash of two Black Hawk helicopters in Mosul, which killed 17 soldiers in the deadliest single incident since the Iraq war began March 20.
However, hostile fire is believed behind three other crashes since Oct. 25. Some witnesses attributed the Mosul crashes to hostile fire.
With Monday's deaths, the U.S. death toll in Iraq grew to 419. According to a government database, a larger number of Americans have died in Iraq than perished in Vietnam through the end of 1964.
On Sunday, Mr. Bush said it had been "a tough week" in Iraq, "but we made progress toward a sovereign and free Iraq."
He was referring to the U.S.-led coalition bowing to demands from Iraqi politicians and agreeing to speed the transfer of power. The new formula, announced Saturday by the U.S.-appointed Iraqi Governing Council, calls for a provisional, sovereign government to be established by June.
In Tikrit, hundreds of U.S. troops in tanks and assault vehicles marched through the crowded downtown area Monday in a show of force intended to deliver a stern warning.
The town, about 120 miles north of Baghdad, is part of a region north and west of Baghdad dominated by Sunni Muslims and regarded as a hotbed of anti-American sentiment.
U.S. forces carried out more than 38 attacks in the area from Sunday night to early Monday, destroying 15 suspected safehouses, three training camps and 14 mortar firing points, said Lt. Col. William MacDonald, a spokesman of the 4th Infantry Division.
Six suspected Saddam loyalists were killed and 21 arrested, he said.
"Clearly, we're sending the message that we do have the ability to run operations across a wide area," said MacDonald. "We have overwhelming combat power that we will utilize in order to go after groups and individuals who have been conducting anti-coalition activities."
In Samara, three Iraqis who fired on American soldiers were killed in an ensuing clash Sunday night. In Muqdadiyah, two Iraqis fired a rocket-propelled grenade on U.S. soldiers on combat patrol aboard a Bradley fighting vehicle. The soldiers returned fire and killed the two, Macdonald said.
While troops have been targeting suspected insurgent targets, U.S. forces have also carried out dozens of raids aimed at apprehending suspects and seizing weapons and bomb-making materials.
One such "cordon-and-search" raid early Monday in Baghdad's middle-class Azamiyah district netted 21 suspects along with 30 Kalashnikov AK-47 automatic rifles, about a dozen shotguns and 10 handguns. Most suspects had violated a coalition rule allowing only one weapon — a single AK-47 — per house.
Residents of the neighborhood next to the Tigris River were furious over the sweep. They said those arrested included men who had revolvers or bird guns that could not have presented a serious threat to the security of the occupying forces.
"Of course everybody has weapons," said Samir al-Hadith, an engineer who works in Saudi Arabia and had returned to Baghdad to check on his home. "There are so many thieves nowadays. We have to defend our families."
CBS News Reporter Charles D'Agata says the raid's main target was the homemade bombs that have proven deadly to several American soldiers.