The bomber targeted workers gathered at Tayaran Square, also wounding at least 22 people, according to the officials.
There was no immediate claim of responsibility for the attack, but suicide bombings are frequently carried out by the Islamic State jihadist group, which overran large areas in 2014 but has since lost significant ground.
While suicide bombings are relatively common in Iraq, they have recently targeted areas outside Baghdad or neighbourhoods on the outer edge of the capital that are easier for militants to access.
