Israeli police say they have arrested a woman in connection with the stabbing death of her three children. Her fourth child was also stabbed but survived.

Police spokesman Micky Rosenfeld said the woman was being questioned. He said a motive for the killings was not yet known. Friends of the family interviewed by Israeli media said they were shocked by the crime.

Rosenfeld said the children -- aged eight, four and one month -- were found stabbed to death in their home Wednesday.

The family lives in a poor, predominantly Bedouin city in southern Israel. Around half of Israel's 180,000 historically nomadic Bedouin live in impoverished government-built communities.