The bombs, which also injured 45 people, went off in the mainly Shiite Muslim district of Sadr City on Sunday, the sources said.
There was no immediate claim of responsibility for the blast, but Daesh (ISIL) Takfiri militants regularly claim such attacks in the capital.
Police said the death toll could rise, Press TV reported.
Earlier in the day, Takfiri Daesh terrorists launched their largest attack in months on the outskirts of the capital, Baghdad, killing at least a dozen Iraqi forces.
Security officials said the terrorists carried out bombing and shooting attacks against several targets in Baghdad’s suburb of Abu Ghraib, which is 25 kilometers (15 miles) west of the city center, on Sunday.
At least 12 security forces have been killed and a number of military posts have been overrun in the attacks, which, according to Iraqi security officials, are still ongoing.
Dozens of militants driving Humvees and pickup trucks with machine guns fixed on them attacked from the nearby Daesh-controlled areas of Garma and Fallujah, army and police sources added.
A military statement said at least four attackers were killed around one of the targeted sites. Another 20 militants have been holed up in a building.
The western suburb of Baghdad has recently been the scene of numerous militant attacks, which have inflicted heavy damage on the area.
On Saturday, nearly 10 people lost their lives and almost three dozen others sustained injuries in a spate of bomb attacks in and around Baghdad.
Daesh has been ravaging the northern and western areas of Iraq ever since June 2014, when it launched a bloody campaign in the country.
The United Nations Assistance Mission for Iraq says a total of 849 Iraqis were killed and 1,450 others injured in acts of terrorism, violence and armed conflict in January.
According to the UN mission, the number of civilian fatalities stood at 490. Violence also claimed the lives of 359 members of the Iraqi security forces. A great portion of the fatalities was recorded in Baghdad, where 299 civilians were killed.