According to a military spokeswoman, an intruder entered the Israeli settlement of Itamar near the northern West Bank city of Nablus around 1 am, made his way into a family home and killed two parents and their three children.

Military units were searching the surrounding area for the assailant, the spokeswoman said. The military would not provide more details. But local media reported that the attack was made with a knife, and neighbors reported hearing shots fired as well.

Military spokesman Maj. Peter Lerner said more than one person may have carried out the crime. Israeli Prime Minister Benjamin Netanyahu demanded that the Palestinian Authority assist in finding those responsible and "halt the incitement in the mosques and via the Palestinian Authority-controlled media." He did not explicitly blame Palestinians for the deaths.

Palestinian Authority Prime Minister Salam Fayyad denounced the killings. The White House condemned the slayings "in the strongest possible terms" and said the killers of the "heinous" act must be held "accountable."

Secretary of State Hillary Clinton added that she was "shocked and deeply saddened" by the incident.