"This is an act of terrorism in every respect. The State of Israel takes a strong line against terrorism regardless of the perpetrators," Benjamin Netanyahu said in a tweet reports BBC News Friday.
But his words, hollow or genuine, may not be enough to calm the situation.
The Palestine Liberation Organisation (PLO), which dominates the Palestinian Authority in the West Bank, said it held the Israeli government "fully responsible for the brutal assassination" of the child, Ali Saad Dawabsha."This is a direct consequence of decades of impunity given by the Israeli government to settler terrorism," it said.
Tensions in the area are running high this week.
Properties deemed illegally built on Palestinian land in the settlement of Beit El were ordered demolished by a court.
One of the houses in the arson attack Thursday night was unoccupied.
But the other was home to a family.
"Resident Ibrahim Dawabsha told Reuters news agency he heard people shouting for help. "We found the parents outside with burns, they said there was another son in the house, we brought him out and then they said there was another boy inside, but we couldn't reach the bedroom because of the fire. He was left inside until rescue forces came," he said."
Four men, and I use that word loosely, carried out the attack.