Palestinian president Mahmud Abbas has described as "abominable" a weekend stabbing attack which killed five Israelis, including a baby, in their beds in a West Bank settlement.
"This act was abominable, inhuman and immoral," the Palestinian leader said in an interview in Arabic with Israeli public radio days after the grisly murder at the Itamar settlement near the northern city of Nablus.
Abbas said the Palestinian security forces had joined forces with Israel to hunt down the killer or killers who were still at large.
He said the Palestinian Authority "did not have any advance knowledge" that an attack was imminent, which could have helped to thwart it.
"We do not know (who was behind this) and we didn't have any information which could have helped us stop this attack. If we had known, we would have tried to stop it with every possible means," Abbas said.
The Palestinian leader, who spoke by phone with Benjamin Netanyahu on Saturday night, said he had agreed with the Israeli premier to conduct a joint investigation into the incident, and that he hoped to "swiftly arrest and bring to justice whoever was responsible for the murders.
The perpetrators broke into the family home late on Friday and in a frenzied stabbing attack killed five members of the Fogel family: three-month-old Hadas, four-year-old Elad, Yoav, 11, and their parents Udi and Ruthie.
Grisly pictures showed the victims lying in pools of blood, each with multiple stab wounds in an attack widely believed to have been carried out by Palestinians.
Over the weekend, Netanyahu blamed Palestinian incitement for creating an atmosphere which led to the killings, with Israeli officials pointing the finger at the weekly sermons preached in mosques across the territories.
But Abbas rejected the charge.
"We are the only country in the Arab and Islamic world -- and I told Netanyahu this -- where we have a formalised text which is preached in all the mosques during Friday prayers.
"These texts do not contain incitement," he said, calling for the establishment of a joint Israeli-Palestinian-American committee to probe the claims.