PSAGOT, West Bank -- At the height of their incantation, as the men in white beards and black clothes were about to condemn Prime Minister Ariel Sharon to death in a spooky ritual known as pulsa denura in Aramaic, someone interrupted to ask: Is the Israeli leader even Jewish?
Then, under a full moon in one of the country's oldest cemeteries, the 20 right-wing extremists who had gathered to summon ''lashes of fire" against Sharon spent two hours splitting hairs over what most Israelis would instantly have recognized as a specious rumor -- that Sharon's mother was a convert. Some participants wanted to know if she had changed her faith according to the tenets of Jewish law. And did the conversion take place before or after Sharon was born?
While other government critics have been blocking roads and marching on the Gaza Strip trying to stop Sharon's plan to dismantle 25 settlements next month, a few hard-liner spiritualists are hoping a Kabballah curse will strike him dead before the withdrawal begins Aug. 17.
Most Israelis seem to regard their antics as Jewish mumbo jumbo (and the suggestion that Sharon or his mother were not Jewish as preposterous).
But with the assassination of another prime minister a decade ago by an ultra-religious Jew still fresh in the public consciousness, the leaked videotape of the ceremony was a top story in the Israeli media. Israeli authorities are taking it seriously enough to weigh indictments against the ceremony's participants.
''Prayer is the only weapon we have," Yosef Dayan, a religious scholar and the former deputy of slain anti-Arab rabbi Meir Kahane, who helped organize the ritual, said this week. ''I knew many people wouldn't like it. My wife doesn't like it. But I knew I had to do it."
Dayan, a 59-year-old whose other pursuit is the resurrection of a biblical-style monarchy in Israel, seems to embrace controversy.
As an army reservist, he was jailed for 40 days in 1982 for refusing to demolish the homes of evacuated settlers in Sinai before the peninsula was returned to Egypt under a peace accord. He said his 20-year-old son, following in his footsteps, recently deserted from the military to avoid participating in next month's withdrawal.
In 1995, Dayan helped lead a pulsa denura ceremony against Prime Minister Yitzhak Rabin, a former war hero who had signed a peace deal with the Palestine Liberation Organization and shook hands with its leader, Yasser Arafat, on the lawn of the White House.
A month after the curse, Rabin was gunned down by ultra-nationalist Yigal Amir, a 25-year-old law student who cited biblical justifications for the murder.
Dayan was questioned after the assassination but no direct link was established between Amir and the pulsa denura rabbis. Today, some analysts believe their deeds are just innocuous enough to be ignored.
''If they're standing in a cemetery making their incantations, they're probably not storing arms in the attic and thinking about how to kill the prime minister," said Yossi Chajes, a specialist on medieval and early Jewish culture at Haifa University.
In fact, Chajes said he had found no reference in ancient texts to pulsa denura as a curse. ''It seems to be a modern, ultra-Orthodox invention."
Sharon, asked about the curse during a visit to Paris this week, responded lightheartedly: ''When does it take effect?"
But most security chiefs, still haunted by the security lapse that led to the Rabin assassination, believe radical rabbis help promote the notion among religious hard-liners that killing a politician is legitimate in order to halt the handover of land promised to Jews in the Bible. Since unveiling his plan to leave Gaza and a part of the West Bank last year, Sharon has been besieged with death threats.
''These people are dangerous and they should be treated the same way we treat [the Islamic militant movement] Hamas," said Carmi Gillon, who headed Israel's Shabak security service -- the agency charged with protecting the country's leaders -- when Rabin was assassinated.
''It's a mistake not to take them seriously," he told Israel's Channel Two television, which aired a video of the ceremony recorded by one of the participants.
Dayan, interviewed at his home in this West Bank settlement overlooking the Palestinian city of Ramallah, said other ''more important" rabbis asked him to perform the pulsa denura publicly after they held a similar ceremony in secret days earlier. He summoned about 35 men who met the criteria for participating: over 40, married, bearded, and scholarly in the Bible.
The men all fasted during the day and immersed themselves in a mikve -- a ritual bath -- before the ceremony. Dayan chose an old cemetery in the northern town of Rosh Pina as his venue for the pulsa denura in memory of a fellow radical buried there, Shlomo Ben-Yosef, who was executed by British authorities in Palestine in 1938 for shooting at a bus transporting Arabs.
By the time the men made the two-hour journey to Rosh Pina, 15 backed out, Dayan said, some fearing arrest.
The ceremony runs about two hours and must be conducted after dark but before midnight. Another stipulation, Dayan said: The curse only works when directed at Jews.
By the time one of the participants interrupted the ceremony with the question of Sharon's parentage, the question plunged the 20 men, who had not eaten since morning, into passionate debate as they stood among tombstones in the old cemetery. Most favored proceeding with the ritual; others wanted to put it off and head home.
The men decided to seek advice from one of the rabbis who participated in the secret ceremony days earlier but could not agree who would make the call.
''Everyone wanted to hear the rabbi's decision with his own ears, but no one had the right cellphone," with a built-in speaker, Dayan said. One of the participants was dispatched to nearby Safed to collect the appropriate technology from a friend. On the advice of the rabbi, the men resumed the ceremony, reciting the curse in unison.
''It's a request we made of the almighty. I don't give him orders," Dayan said in his home, referring to the curse. ''But I believe it will work."