A man wearing a belt of explosives walked into the lobby of Baghdad's Mansour Hotel, approached the reception desk and detonated his bomb, said a police official, speaking on condition of anonymity. Seven people were killed and at least 12 others were wounded, police reported.
The high-rise hotel, on the banks of the Tigris River, houses the Chinese Embassy and several news organizations. A number of Iraqi parliament members also stay at the Mansour.
Saif al-Rubaie, 28, a worker in the reception area, said all the casualties were Iraqis, most employees in the reception area.
Yarmouk Hospital in west Baghdad received seven bodies and seven wounded from the bombing, a medical official there reported.
The attack was the fifth in a string of homicide and other bombings, from Mosul and Beiji in the north to Hillah in the south. Two were aimed at U.S. targets, but no U.S. casualties were reported.
The deadliest occurred at a police station in Beiji, 155 miles north of Baghdad, at 8:30 a.m., when at least nine civilians were killed and 21 others wounded, police and medical officials reported.
American troops share the post with the local police, on the main road in central Beiji. One wounded man said random gunfire came from the building after the blast.
"I was at the grocery market when the explosion occurred and I ran with others to the site to see if there were any casualties and I was shot by fire from police station," said Khalaf Salim, 40.
About 45 minutes later, another homicide car bomb exploded at a joint U.S.-Iraqi army checkpoint in central Siniyah, 9 miles west of Beiji, killing two Iraqi soldiers and wounding three others, an Iraqi army officer reported.
Eyewitnesses said a U.S. Humvee vehicle was damaged in the blast, but "there were no U.S. casualties in both incidents," said Spc. Brian Bucy, a spokesman for Task Force Lightning, the U.S. military command covering the Beiji area.
American aircraft quickly appeared over the Beiji area and attacked suspected insurgent targets, eyewitnesses said.
Earlier in the morning, a homicide car bomber struck a checkpoint near the governor's offices in the predominantly Shiite southern city of Hillah, killing at least eight people and wounding 31, police said.
It was the second such attack in Hillah in three days. A parked car packed with explosives blew up on Saturday in the center of the city, 60 miles south of Baghdad, killing two people.
Three of the eight killed in the 6:30 a.m. explosion were policemen, as were at least four of the wounded, said a spokesman for the provincial police department.
The attacker drove his car into a checkpoint that leads to the headquarters of the Babil provincial government.
Police officer Baha Abdul-Sadda, 21, said he saw a red sedan speeding toward the headquarters, surprising police at the checkpoint and on the building's roof.
"The homicide bomber took advantage of the early hour and intended to hit the metal barrier to get inside to hit the building, but the car exploded prematurely at the metal barrier," he said. Abdul-Sadda, who suffered a head injury when thrown against a wall by the blast, spoke from his hospital bed.
The blast damaged the concrete walls surrounding the main building and shattered glass, but relatively few people were in the area because of the early hour, limiting the casualties, the police spokesman said.
Hillah, the capital of Babil, has been the target of some of the deadliest car bomb attacks by suspected Sunni Muslim extremists in the four years of insurgency and sectarian killings in Iraq.
The fourth bomb was in a parked car that exploded in the center of the northern city of Mosul, killing one civilian and wounding 20 others, police Brig. Mohammed al-Wakaa said. He said there were no police or military targets at the site.
In other violence, two mortar rounds Monday morning struck Baghdad's Fadhil district, a Sunni enclave in the central city, killing two civilians and wounding three others, police said.
In the southern city of Basra, the body of a kidnapped Iraqi army intelligence officer, Lt. Col. Faris Mohammed of the 10th Division, was found Sunday in the al-Fursi district, it was reported Monday by a British military spokesman in Basra.
Mohammed had been seized from his car on Saturday while being driven from nearby Shaibah to Basra. His driver and bodyguard were released unharmed, spokesman Maj. Matthew Bird said. "The Iraqi army is continuing its investigation into the incident," he said.
Iraqi police and other authorities often speak only on condition of anonymity, because of concerns over personal security or because they are not authorized to divulge information.