Palestinian President Mahmoud Abbas said on Monday the killing of a Israeli settler couple and three of their children was "inhuman", telling Israel he was determined to help catch those responsible.
"This was inhuman and immoral. We deplore this incident, without a doubt. It is an abomination," Abbas told Israel Radio.
"I can't imagine a four-month-old child murdered," he said, speaking in Arabic. "Children, of all things ... Any person who has a sense of humanity would be pained and driven to tears by such sights."
Friday night's knife rampage in a home in Itamar settlement, which Israel blamed on Palestinians still at large, ruptured the relative quiet of the occupied West Bank and underscored the stalemate between Abbas and Netanyahu over prospects for peace.
Netanyahu said on Sunday that "alarming incitement in Palestinian schools, mosques and media" had prepared the ground for the Itamar attack.
Abbas rejected the allegation, saying his Palestinian Authority was "the only place in the Arab and Muslim world" where the government set weekly guidelines for mosque sermons.
"If it (a sermon) is incitement, it is stopped. If it is not incitement, they can go ahead," he said. The Palestinians, with international support, have pursued a law-and-order drive in the West Bank, which they want back as part of their future state. They see Israeli settlements as an obstacle and insist building stops before peace talks resume.
Netanyahu has rejected that demand and responded to the Itamar attack by approving hundreds of new settler homes. Abbas said he had telephoned Netanyahu to offer condolences as well as help.
"Had we had advance intelligence, we would have prevented this," he said. "We want to know who did this. We hope to get results and identify the perpetrator and bring him to justice."