Roadside bombs killed eight US soldiers in separate attacks in Diyala Province and Baghdad and a car bomb claimed 30 more lives in a wholesale food market in a part of the Iraqi capital where sectarian tensions are on the rise.
In all, at least 95 Iraqis were killed or found dead nationwide on Sunday, police reported.
They included 12 policemen in Samarra, among them the city's police chief, who died when Sunni insurgents launched a suicide car bombing and other attacks on police headquarters.
The deadliest attack against US forces occurred in Diyala, where six US soldiers and a European journalist were killed when a massive bomb destroyed their vehicle, the US military said.
Two US soldiers were wounded, the military said. The US did not identify the journalist.
Two other US soldiers died on Sunday in separate bombings in Baghdad.
The military on Sunday also reported three other deaths -- two Marines in a blast on Saturday in Anbar Province and a soldier who died on Sunday in a non-combat incident in northern Iraq.
Those deaths raised to at least 3,373 the number of US military members who have died since the Iraq War started in March 2003.
The market bombing occurred about noon in the Baiyaa district of western Baghdad, shattering vehicles, ripping roofs off nearby buildings and collapsing storefronts. Police said about 80 people were injured in addition to the 30 dead.
Following the horrific blast, blood pooled on the dirt streets. Hospital officials said two pickup trucks filled with body parts were brought to the morgue.
"I was waiting near a shop to lift some boxes, when I saw the owner of the shop collapse," said Sattar Hussein, 22, who works in the market. "I helped him inside the shop, but he was already dead. The next thing I felt was pain in my left shoulder and some people rushing me to the hospital."
Ali Hamid, 25, who owns a shop in the market, said he was selling soft drinks when the blast knocked him unconscious.
"The next thing I remember is some people putting me in a pickup with two dead bodies and rushing me to the hospital," he said. He called the attack "a terrorist act aimed at creating more sectarian tension and strife."
No group claimed responsibility for the attack, which followed allegations by Sunni politicians that Shiite militias have resumed their campaign to expel Sunnis from Baiyaa.
Most of the shops in the market were believed owned by Shiites.
That raised speculation that the bombing was carried out by Sunni hardliners in reprisal for the alleged expulsions, which were believed to have slowed across the capital since the start of the Baghdad security crackdown on Feb. 14.
The attacks in Samarra began when a suicide car bomber struck the police headquarters. Following the blast, dozens of insurgents -- some wearing masks and wielding video cameras -- opened fire on the building and at least one police checkpoint, witnesses said.
US paratroopers from the 82nd Airborne Division came under small arms and rocket-propelled grenade fire when they rushed to the scene, the US military said. Two Americans were wounded and a vehicle was damaged.
The police chief, Colonel Jalil Nahi Hassoun, and 11 other policemen were killed, officials said.
Samarra was the scene of the Feb. 22, 2006, bombing that destroyed a major Shiite shrine and triggered the wave of Sunni-Shiite reprisal attacks that has plunged the country into civil war. US and Iraqi officials blame that bombing on al-Qaeda, which has been active in the city for years.