-- On just about any day of the week, Qusay Kaabi could look around the popular Ibn Zamboor restaurant and see a sea of light blue, the color of Iraqi police uniforms.

"The restaurant sometimes looked like a police station," said Kaabi, 29, who baked bread in clay ovens at the back of the popular eatery, just a few hundred yards from a real police station and only slightly farther from Baghdad's Green Zone, the fortified compound where key Iraqi government offices and several foreign embassies are located.

On Sunday afternoon, the busy restaurant's familiar blue aspect was smeared with blood and smudged by billowing smoke. At 2:30 p.m., an unidentified man walked up to the entrance of Ibn Zamboor and detonated an explosive vest filled with ball bearings, killing at least 23 people and wounding more than 30, according to witnesses and survivors.

"There were a number of policemen outside the restaurant having tea from Alaa, the tea man. There were two tables with chairs around them where the policemen were sitting. Then a suicide bomber came close to them and blew himself up," Kaabi said.

"It was a very loud explosion, and the restaurant was filled with smoke and dust."

Initial reports by the Iraqi Defense Ministry said two of the dead were police officers; later news service reports put the number as high as seven. Of 13 restaurant employees working at the time of the attack, Kaabi said, he and two others were the only ones to escape death or injury.

The restaurant bombing was the second of two suicide attacks that killed more than two dozen people in Baghdad on Sunday. Two hours earlier, a driver following a police convoy on Baghdad's north side detonated a bomb in his car that killed two people and wounded 27, according to the Defense Ministry. Two of the wounded were Iraqi policemen.

In the northern city of Tikrit, meanwhile, a suicide bomber wearing a police uniform drove a car rigged with explosives into the main gate of a U.S. military base, where Iraqi soldiers were manning a security checkpoint. The explosion killed five Iraqis, including two soldiers.

"The vehicle that usually brings food for the base arrived, and behind it there was a yellow Ford driven by a man wearing a police uniform," said a survivor of the blast, Qais Mohammed Shammari, an Iraqi army warrant officer who suffered wounds on his face, neck, abdomen and arms. "We thought that he came for work. After we finished searching the food vehicle, I waved to him to come closer to be searched, then his lips were saying something and he drove fast and blew up the car. I saw death in front of my eyes."

The flurry of suicide attacks occurred as U.S. Marines and Iraqi troops conducted a third day of operations in far western Iraq aimed at wiping out insurgents and their support network in Karabilah and nearby border towns. The coordinated ground and air campaign, called Operation Spear, suffered its first American fatality on Saturday, when a Marine was killed by small-arms fire in Karabilah, according to a statement by the Marines.

In Qaim, just west of Karabilah, residents reported that U.S. airstrikes had destroyed more than a dozen buildings. Hamdi Alousi, head of the local hospital, said 32 people had been killed in the fighting there, including 14 civilians. His account could not be independently confirmed. Khalid Karbuli, a tribal leader, said more than 300 families in Qaim had been without water and electricity for three days.

Ali Naji, a preacher at a mosque in Qaim, blamed the violence and hardship on the group al Qaeda in Iraq and its leader, Abu Musab Zarqawi, who U.S. commanders said has been smuggling foreign fighters into Iraq from Syria and marshaling them in the border area before deploying them elsewhere in the country.

"Zarqawi's group is responsible for this destruction," said the preacher. "They don't care about us and the city. They want destruction so they can say that they are fighting the crusaders, and by that they want to fool the Iraqis."

Fighting was also reported outside Fallujah, 35 miles west of Baghdad, where U.S. forces carried out a massive assault in November to wrest control of the city from insurgents. On Sunday, according to a Marine statement, insurgents attacked a Marine patrol in three waves -- first with rocket-propelled grenades and small arms, then with machine-gun fire and finally with a car bomb. The Marines repulsed each attack, killing a total of 15 insurgents, the statement said.

A statement posted on the Internet asserted responsibility for the Baghdad restaurant bombing in the name of Zarqawi's organization, the Associated Press reported. The statement said that the bomber was from Qaim and that "the restaurant is only frequented by the officers, police, spies and collaborators in the Green Zone. It was their lunch time."

In the chaotic aftermath of the attack on the eatery, a stream of police cars carried the dead and wounded to a nearby hospital while survivors scattered from the scene in search of someplace safe to catch their breath and call loved ones, said Abdul Rahman, owner of the nearby Khokha supermarket.

As one police officer in the store assured his superiors by telephone that "I am okay -- just wounded but okay," Abdul Rahman told a reporter that he feared for the lives of the restaurant's employees. "Abu Fahad, the shawarma man, is still alive," he said. "I saw him in a police car. He was bleeding and his side was burned.

"He is so nice, and I like his food. I hope he will be okay."

Special correspondents Kareem Sadoon, Moayad Jabbar and Jawad Munshed in Baghdad and Salih Saif Aldinin Tikrit contributed to this report.

From their balcony overlooking the scene, an Iraqi man and woman react to the aftermath of a suicide blast at a kebab restaurant near Baghdad's Green Zone. Members of Iraq's police and military walk through the restaurant site, where the attacker detonated an explosive vest filled with ball bearings.