Palestinians may not be responsible for killing a family of five Israelis in Itamar settlement overnight Friday, the Gaza government said Sunday.

Israeli authorities immediately blamed Palestinians for the attack, and Israeli Prime Minister Benjamin Netanyahu accused the Palestinian Authority of "daily incitement" against Israel in his response to the killings.

However, Gaza government spokesman Taher An-Nunu said the Israeli government should not rule out the possibility that the attack was perpetrated by Israeli criminals.

Hamas has denied any involvement in the attack.

A shadowy faction calling itself the "Imad Mughniyya Group" claimed responsibility for the attack but Israeli authorities have dismissed the group's claims in the past. It has claimed responsibility for other operations in the past that may have been the work of others.

So far, no other faction has claimed involvement.

An-Nunu warned Israel against using the killings to justify an escalation in violence against the Gaza Strip.

He said that relocating Israel's domestic crises toward incitement against Palestinians was "unacceptable political blackmail."

Within 24 hours of the attack, Israeli ministers met and decided to approve a huge expansion in Jewish-only settlements in the West Bank.

Settlers have launched a series of attacks on Palestinians across the West Bank, storming villages, harassing residents in their homes, smashing shops and throwing rocks at Palestinian cars.

The international community recognizes that building Jewish-only housing on occupied Palestinian land is illegal according to international law and the Geneva Convention, and has repeatedly called on Israel to halt construction.

Israel's refusal led to the collapse of the last round of negotiations in September.