Israel's intelligence service has warned of growing concern for Ariel Sharon's safety as the far-right gives increasing support to violent resistance to his plan to remove Jewish settlers from Gaza and parts of the West Bank.
The Shin Bet has increased protection for the prime minister after threats by extremists to defend the settlements by force, and religious rulings by some rabbis justifying violence.
Amid echoes of the assassination of the then prime minister Yitzhak Rabin nine years ago, Mr Sharon told parliament he was disturbed by the warnings.
"It pains me that, as someone who all his life defended Jews in the wars of Israel, I now need defense against Jews, for fear someone might try to harm me," he said. "This is something that must be uprooted. All these conferences and rhetoric cannot be allowed."
Israel's security minister, Tzachi Hanegbi, said Tuesday he believed that there were Jewish extremists who had already decided to kill a top official.
"There are those who have already made the decision, that when the time comes, they will save the people of Israel," Mr Hanegbi said.
"They will try to kill a minister, prime minister, a policeman, a military officer, I have no doubt. They don't always succeed and they don't always have the means to carry out the acts. But we are not lacking extremists."
Last week the rabbi of Jerusalem's old city, Avigdor Neventzal, told colleagues from the settlements that anyone who gave up part of Israel to non-Jews was open to a din rodef religious licence for a Jew to kill a Jew. The rabbi qualified his ruling by saying it was not possible to put the ruling into practice in modern times.
Two cabinet ministers drew parallels with Rabin's assassination by Yigal Amir, who used din rodef as his justification for the murder. The justice minister, Yosef Lapid, said: "These are examples of playing with fire, and the grave of Yitzhak Rabin is a reminder of this."
Among those who have supported violence to defend the settlements is Uri Elitzur, chief of staff to former prime minister Binyamin Netanyahu.
Mr Rabin's family has accused Mr Netanyahu and other rightwing politicians of contributing to the climate that led to the 1995 murder.
Earlier this week the Shin Bet chief, Avi Dichter, warned the cabinet about a process of "radicalisation" on the far right.
He singled out statements by some rabbis and leaders of the settler movement giving religious justifications for violent resistance to the forced evacuation of about 7,500 Jews from Gaza, and even attacks on politicians and senior military officials.
"I am worried about an escalation in violence," he said.
The outlawed far-right Jewish group Kach said this week that there were "no more red lines" when it came to the actions justified "to prevent the expulsion of Jews from their land".
On Sunday, Israeli television showed film of three settlers associated with Kach instructing pupils at a school in Gaza to resist the evacuation by beating up officials involved in the removals.
One of them, Itamar Ben-Gvir, told the Jerusalem Post the settlers would defend their homes any way they could. "I don't believe we will be the first to open fire, but if the security forces fire on us then the settlers will fire back," he said.
Mr Dichter told the cabinet that a senior army rabbi, Lieutenant Colonel Yekutiel Wisner, had been beaten up by Kach supporters in Jerusalem because of his involvement in the removal of a synagogue from an illegal settlement.
More moderate rabbis have called for the prosecution of those who incite violence.