Violence against coalition forces continued Tuesday as three explosions rocked central Baghdad, with two mortars landing in the city center, the U.S. military confirmed.

The Coalition Press Information Center said none of the explosions occurred inside the Coalition Provisional Authority (search), the headquarters of the U.S. occupation, as was earlier reported. But the explosions did occur within the U.S.-controlled Green Zone, a square-mile area along the western bank of the Tigris where the CPA compound is located, officials said.

Early Wednesday, a U.S. army compound in the northern city of Mosul (search) was hit by rocket-propelled grenades, the military said. There were no casualties.

At least three people were wounded in Tuesday's attack, said Pentagon spokesman Lt. Col. Jim Cassella. He said it was not clear whether the injured were military or civilian personnel or whether they were Americans.

Officials weren't sure yet if the weapons were mortars or rockets.

The CPA building is the headquarters of U.S. civilian administrator L. Paul Bremer and the former presidential palace of Saddam Hussein.

Three large explosions could be heard about 7:45 p.m. near the northern end of the U.S. compound near the al-Jamhuriya Bridge over the Tigris River.

The Green Zone is a cordoned-off region that includes the palace, the Al Rashid hotel (search), where most U.S. workers have been staying, and other buildings. On Oct. 26, insurgents pelted the Al Rashid with rockets, killing an American soldier and sparking a hurried evacuation of the hotel.

U.S. military officials in Baghdad told Fox News they were investigating the cause of the explosions. There was mortar fire Monday night in the same general area, hitting a U.S. Army base compound but not causing any casualties.

"We're back to finding these terrorists and bringing them to justice," President Bush told reporters while touring wildfire damage in California. "These people want to — 'these people' being the terrorists and those who would kill innocent life — want us to retreat, they want us to leave, because they know that a free and peaceful Iraq in their midst will damage their cause. And we will stay the course, we will do our job."

Earlier in the day, another American soldier was killed in a roadside bombing in Baghdad Tuesday as guerillas launched new attacks against coalition forces in Iraq.

Two more Americans, also from the 1st Armored Division, were also wounded when their military vehicle struck an improvised explosive device around 10:10 a.m. local time.

Another soldier was killed Monday and one other wounded when their vehicle struck a land mine in Tikrit.

In Mosul, gunmen killed a provincial judge Tuesday near his home. Ismail Youssef, a Christian, was a deputy to the head of the appeal courts in Nineveh province. On Monday, the head of an Iraqi court who was investigating members of Saddam Hussein's Baath Party, Muhan Jabr al-Shuweily, was abducted and murdered in the southern city Najaf.

A colleague who was spared said he believed the killers were supporters of Saddam.

And a neighborhood council chairman in west Baghdad, Mustafa Zaidan al-Khaleefa, 47, was fatally shot from a passing car late Sunday.

"I think we have to back up a moment and understand we're in a war, we're in a guerilla war," Sen. Chuck Hagel, R-Neb., told Fox News after the CPA attacks.

Arabic language satellite television station Al-Jazeera reported an ambush Tuesday near Samara north of the capital and broadcast pictures of cheering Iraqis displaying American ammunition as a truck burned in the background.

Meanwhile, Spain said it was withdrawing much of its diplomatic staff from Iraq for security reasons. The Embassy will remain open but with a skeleton staff, far short of the usual 29 workers located there.

"We have taken staff out of Baghdad temporarily given that it is a very complicated moment," Spanish Foreign Minister Ana Palacio was quoted as saying by the Spanish news agency Europa Press.

Bulgaria and the Netherlands moved Embassy staff in Iraq to Jordan last month, both citing safety concerns following attacks on diplomatic and humanitarian agencies including the deadly bombings at the Turkish Embassy and the U.N. headquarters.

Insurgent Attacks Continue

Elsewhere, witnesses said insurgents ambushed a U.S. patrol Tuesday with rocket-propelled grenades in the city of Khaldiyah, located west of Baghdad in the volatile "Sunni Triangle." And a police station in the northern city of Mosul was struck overnight by a rocket-propelled grenade, the military said Tuesday. There were no reports of casualties in either incident.

Also in Mosul, insurgents using small-arms fire and rocket-propelled grenades Tuesday attacked a hotel housing American troops but caused no casualties, the military said. Three of the grenades hit the building and two others landed in the compound.

U.S. troops, meanwhile, raided the village of Karasia near Tikrit late Monday, seizing two suspects, Kalashnikov rifles, 14 mortar rounds, a mortar tube and rocket-propelled grenades and launchers, the military said.

A Monday explosion in Karbala, 65 miles south of Baghdad, killed at least one person and injured 12. The blast occurred about 100 yards from the gold-domed Imam Hussein shrine.

'There Was a Lot of People Screaming'

The latest deaths came as U.S. troops continued to scour Iraq for anti-aircraft missiles following Sunday's deadly CH-47 Chinook (search) helicopter ambush that killed 15 U.S. troops and injured about 20 more. It was the largest U.S. death toll in any single action since the invasion of Iraq began March 20.

The casualties brought the number of American soldiers killed in Iraq in November to 23, most in the weekend crash of a transport helicopter shot down Sunday west of Baghdad.

"Everybody was just laid out everywhere, and they were trying to search for most of the people that were left within the rubble," helicopter survivor Cpl. David Tennant said in a television interview. "There was a lot of people screaming. I just remember waking up in the middle of the rubble, trying to escape, trying to get out of the burning metal."

The injured were taken to Ramstein Air Base in Germany and treated at the U.S. military's Landstuhl Regional Medical Center (search). Nine were admitted to the intensive care unit, including five in serious condition. Many were still on ventilators.

Soldiers who died in the chopper attack were brought to the military morgue at Dover Air Force Base in Delaware Monday night. The Dover morgue is the largest in the Defense Department.

Fox News' Bret Baier, Steve Harrigan, Dana Lewis and The Associated Press contributed to this report.