Insurgents killed four employees from the Iraqi Red Crescent and nine others in three separate attacks in Baghdad's southern districts on Saturday, a security official said.
Four Iraqi humanitarian workers were killed and three others wounded when gunmen ambushed their minibus in the capital's mixed Sunni-Shiite district of Zafaraniyah, the official said.
Also in Zafaraniyah, a group of gargabe collectors was hit by a roadside bomb, which killed one and wounded eight others, the official said.
In nearby Saydiyah, another mixed district, unidentified gunmen shot dead five civilians and wounded one more, he added.
In Al-Risala district, also located in southern Baghdad, a series of mortar rounds slammed into a residential area killing three people and wounding 10 others, including women and children, the official said.
Insurgents have carried out a steady stream of attacks in Baghdad, including high-profile car bombs, despite a massive 10-week-old security crackdown by Iraqi and US troops in the capital since February 14.
While US commanders say the number of sectarian death squad murders has come down by about a third since the plan was launched, bomb attacks have kept up the overall level of casualties.