Most of the people killed were children who were attending an opening ceremony for a new water-pumping station in the southwest of the capital when two car bombs exploded.
Moments later, a third car bomb went off about a kilometer away at an Iraqi National Guard checkpoint.
The three bombings followed a separate suicide car bombing west of the capital in Abu Ghurayb, which killed at least two Iraqi police, one U.S. soldier, and wounded many other people.
In the northern city of Tall Afar, four Iraqis were killed and 16 people were wounded in a car bombing.
Also today, the U.S. military said insurgents fired a rocket at coalition forces outside Baghdad, killing one U.S. soldier and wounding seven others.
In overnight fighting, U.S. warplanes again bombed suspected militant targets in the Iraqi insurgent stronghold of Al-Fallujah.
The U.S. military command in Baghdad said the overnight attack was aimed at a "known hideout" of supporters of Jordanian militant Abu Musab al-Zarqawi.
Doctors at Al-Fallujah's main hospital said at least three people were killed.
A militant group believed to be led by al-Zarqawi has claimed responsibility for a number of recent attacks and hostage takings in Iraq. The group is now threatening to behead a British hostage they are holding.
British Prime Minister Tony Blair yesterday said his government would respond if Kenneth Bigley's abductors made contact.
"We can't make contact with [the captors]," Blair said. "They made no attempt to have contact with us at all. Of course, if they did make contact, it would be something that we would immediately respond to."
Meanwhile, U.S. officials have said they want to see Syria take concrete measures to prevent militants from entering Iraq after it agreed to tighten its border with the neighboring country.
U.S. officials said the agreement was reached yesterday following talks in Damascus between U.S., Syrian, and Iraqi officials.
(wire reports)For the latest news on Iraq, see RFE/RL's webpage on "The New Iraq".