Israel hunted for the perpetrators of a grisly murder of a family of five in a remote West Bank settlement Saturday, appealing for help from the Palestinian Authority, which sent security forces to join the manhunt.
The knife attack, which killed two young children, a baby and their parents as they slept, was the deadliest in years. It comes at a delicate moment, with pressure building on Israel to launch a new peace initiative and the Palestinians pushing for world recognition of an independent state _ with or without a peace deal.
Israeli forces set up checkpoints throughout the area surrounding the Itamar settlement in the northern West Bank and were still sweeping the region late into Saturday. Military officials said they had made some arrests, but wouldn't provide details.
The governor of the nearby Palestinian city of Nablus, Jibril Bakri, told The Associated Press that Palestinian security forces were also searching for suspects. It was a rare instance of the two sides both searching for militant suspects, though Israeli forces and those of the Western-backed Palestinian Authority in the West Bank do cooperate on security issues.
Prime Minister Benjamin Netanyahu convened a special security meeting to decide upon further action, saying he was "deeply shocked" by the attack.
"We all know, as those who want to strike at us will know, that the future of the settlements will not be decided upon by terror," he said. "Israel will not stand by idly after such a despicable murder and will act vigorously to safeguard the lives of the citizens of Israel and punish the murderers."
The Al Aqsa Martyrs' Brigades, a mostly defunct Palestinian militant group, took responsibility for the attack. However, they frequently claim to be behind attacks they didn't do in hopes of raising their profile.
"Violence does not justify violence, we condemn it completely, whoever does it and whoever the victims are," Palestinian Prime Minister Salam Fayyad told The Associated Press.
Palestinian President Mahmoud Abbas called Netanyahu to condemn the attack as well.
Netanyahu said that was not enough and demanded Palestinians stop incitement "that is going on every day in their schools, in their mosques, in the media outlets they control."
"It is time to stop this double speak, because the Palestinian Authority speaks peace outwards but allows incitement inwards," he said in a speech later Saturday.
In Gaza, a Hamas official applauded the attack and local residents celebrated the killing of the settlers.
TV footage from the scene showed children's toys covered in blood and furniture tipped over. Israeli officials said at least one Palestinian militant infiltrated the settlement, entered the family home and stabbed the parents and three of their children, ages 11, 3 and 4 months, as they slept.
Two young children asleep in another part of the house survived. Another family member, a 12-year-old girl, was away at a youth group function when the attack occurred. She arrived home to discover the carnage and then alerted authorities.
Israeli President Shimon Peres called the attack "one of the ugliest we have known."
"The murder of parents and their little children ... indicates a loss of humanity," he said. "No religion and no faith in the world condones such atrocious acts."
The bloody nature of the attack immediately raised concerns about Jewish retribution. Col. Nimrod Aloni, a West Bank brigade commander, said the military was preparing for possible clashes between Palestinians and settlers.
Israeli settlers sometimes carry out revenge attacks on Palestinian targets, either in retaliation for Palestinian violence or for Israeli government actions against settlers. The attacks, known as "price tag" diplomacy, include vandalism, destruction of crops or physical attacks.
Netanyahu called on all Israelis "to act with restraint and not to take the law into their own hands."
Itamar is a small and extreme settlement that has rocky relations with the nearby Palestinian towns and villages.
The overnight attack was the first against settlers in months and the deadliest 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.
A 10-month Israeli freeze of new settlement construction expired last September, but a de facto slowdown has since continued on the ground, angering settlers.
Ron Nahman, mayor of the Ariel settlement, called on the government to respond to the "massacre" by resuming construction in earnest. He said anything else would send a message to Arabs that "you can do anything against the settlers."
The attack occurred on the Jewish Sabbath when the observant are prohibited from working and most physical activity, instead spending the day in prayer or rest. Itamar is an observant community and there was no official comment from residents there.
The White House condemned the attack and offering condolences to the Israeli people.
"There is no possible justification for the killing of parents and children in their home. We call on the Palestinian Authority to unequivocally condemn this terrorist attack and for the perpetrators of this heinous crime to be held accountable."
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 U.N. Special Coordinator for the Middle East Peace Process, Robert Serry issued a statement in which condemned the "shocking murder" and called for those responsible to be brought to justice.