BAGHDAD  A series of bombings, beheadings and shootings rippled through Iraq on Monday, leaving at least 23 people dead, including 9 children, and intensifying concern about a spike in violence with less than two weeks until national elections.

The authorities detected no discernible pattern to the violence, with rockets exploding in Baghdad’s heavily fortified Green Zone, car bombings aimed at government buildings, assassinations of security officers and government officials and the killings of two families in their homes in Baghdad.

The killings of the families were reminiscent of the attacks common during the height of the bloodletting between Sunnis and Shiites in Iraq a few years ago.

In the largely Shiite town of Madaen, south of Baghdad, a gang of gunmen stormed a home of a family and killed all eight people there, including six children.