The attack came as Iraq's Muslims observe Ramadan, a monthlong period of prayer and daytime fasting.

A police officer said the robbers surprised the mother of three in the 4:30 a.m. assault in the Shiite neighborhood of Sadr City. Her children were upstairs and were not hurt, he said.

The men ransacked the room but, apparently afraid the woman's screams may have raised alarm, fled the scene empty-handed, the official added.

A doctor at the neighborhood's Imam Ali hospital said the woman was beaten in the head and stabbed in several places.

Meanwhile, police and hospital officials said 14 people were wounded Friday afternoon in three successive bombings in the city of Samarra, 60 miles (95 kilometers) north of Baghdad.

Samarra police said bombers first blew the house of a local policeman around 3:15 p.m. Minutes later, a second explosion hit bystanders who had gathered on a road near the destroyed house. And shortly after that, the home of a Sunni security guard in Samarra was also blown up, police officials said.

All officials spoke on condition of anonymity because they were not authorized to talk to the media.