JERUSALEM -- The Israeli military vowed Saturday to "bring to justice" attackers who knifed five members of the same Israeli family to death as they slept in a West Bank settlement.
The attack happened in the settlement of Itamar late Friday, killing a husband and wife, and an 11-year-old, a 3-year-old and a baby.
Authorities believe it was undertaken by Palestinians who infiltrated the settlement. Calls to Palestinian authorities were not immediately returned.
"This was a very harsh terror attack, a whole family was wiped out by despicable cowardly murderers who came in the dead of night and killed innocent children, a woman and man as they slept," said Avi Mizrachi, commander of the military's Central Command.
"We are in pursuit of the perpetrators and I estimate that we will quickly get our hands on them and bring them to justice," he said.
Footage from the scene broadcast on Israeli media showed children's toys covered in blood and furniture tipped over.
Israeli media said another family member, a 12-year-old girl, was away at a youth group function when the attack occurred. She found the carnage when she came home and alerted the authorities.
The Israeli military set up checkpoints and searched the area.
Defense Minister Ehud Barak convened security and intelligence personnel overnight and conferred with Prime Minister Benjamin Netanyahu, his office said in a statement.
Israeli Foreign Minister Avigdor Lieberman said he would file a complaint with the U.N. over the attack and that he expects "worldwide condemnation of the satanic murder of an entire family."
The attack is the first against settlers in months and the first of its scope in years, marking a rare outburst of violence during a relatively calm period. It comes as Israeli-Palestinian peace efforts are at a standstill and could complicate efforts to restart them.
Peace talks between the two sides collapsed last year over disputes over Israeli settlements in the West Bank, territory Palestinians envision as part of their future state.
"Now maybe the international community that condemns us all the time will understand who we are dealing with here, in every peace agreement they want us to sign, they need to understand who is on the other side," said Danny Danon, a hawkish member of Israeli Prime Minister Benjamin Netanyahu's Likud party.
The attack was reminiscent of a similar one against Itamar in June 2002, during the height of the violent Palestinian uprising, when a gunmen burst into the home of a family and opened fire.
The mother of the family and three of her children were murdered. Another two children were seriously injured and a local security official was shot to death as he tried to help.