Baghdad, Iraq (CNN) -- In a rare attack against a humanitarian group, militants killed five workers and wounded two security officers Monday, officials said.
Four gunmen broke into the Mawtini charity office in Adhamiya, a Sunni neighborhood in Baghdad, Ministry of Interior officials said.
They shot and killed five employees, officials said, and planted a bomb in the office. Iraqi security forces later arrived at the crime scene, and two soldiers were wounded when the bomb exploded, officials said.
The Mawtini charity serves poor families, orphans and widows affected by the sectarian violence, officials said.
The security forces are still investigating the killings. They have yet to determine a motive, officials said.
Monday's violence followed a bombing on Sunday that killed one civilian and wounded four others in the country's capital.
CNN's Mohammed Tawfeeq contributed to this report.