Ann Arbor police say a man repeatedly stabbed his mother in their home on the city's northwest side early today, causing serious injuries.

Officers arrested the 25-year-old man at the home in the 1400 block of Hatcher Crescent and took him to the Washtenaw County Jail, police spokeswoman Lt. Renee Bush said.

The 49-year-old victim suffered wounds to her torso after being stabbed with a knife at about 6 a.m., police said. She was taken by ambulance to the University of Michigan Hospital.

Officers responded after the woman called 911 to report that her son stabbed her, police said. Police found her lying on the floor, but she was conscious and was able to speak with officers, Bush said. 

It's unclear what led to the stabbing, Bush said. Charges are pending.