Jerusalem ? Prime Minister Ariel Sharon underwent hours of surgery after suffering a life-threatening stroke, but doctors resumed operating early today after a brain scan revealed he required more treatment. Powers were transferred to his deputy, Ehud Olmert.

Sharon fell ill at his ranch Wednesday evening and was rushed to Hadassah Hospital in Jerusalem, where he was diagnosed with a cerebral hemorrhage. Doctors began emergency surgery about midnight to stop “massive, wide-spread bleeding” in his brain.

Media reports said the surgery had ended after more than six hours. But Hadassah Hospital Director Mor-Yosef said that while the bleeding had stopped, Sharon was returned to surgery in “serious condition.”

“We are continuing with the same operation, and there are more areas that need to be treated,” Mor-Yosef said without elaborating.

Surgery apparently had been complicated by blood thinners he had been given following a mild stroke on Dec. 18, and the medication may also have contributed to Wednesday’s stroke.

Mor-Yosef did not address Sharon’s prognosis, but neurosurgeons not involved in Sharon’s treatment said a full recovery was not likely following such a massive stroke. They said it usually takes at least a day after the surgery to determine the extent of any damage.

Olmert was to convene the Cabinet at 9 a.m. today for a special session.

An ambulance brought Sharon to the Jerusalem hospital only hours before the hard-charging, overweight, 77-year-old Israeli leader had been scheduled to undergo a procedure to seal a hole in his heart that contributed to a mild stroke on Dec. 18.

Time of upheaval

Sharon’s cerebral hemorrhage, or bleeding stroke, came at a time of upheaval among Palestinian factions in Gaza and in the midst of both Israeli and Palestinian election campaigns. Sharon’s absence would slow momentum toward peacemaking with the Palestinians and leave a major vacuum at the head of his new Kadima party, which was expected to head a government after the March 28 vote.

In a written statement, President Bush praised Sharon as “a man of courage and peace,” saying he and first lady Laura Bush “share the concerns of the Israeli people … and we are praying for his recovery.”

Israeli Chief Rabbi Yona Metzger called on Israelis to read Psalms and pray for Sharon. “We are very, very worried,” he said, and prayed for “mercy from Heaven.”

Pan-Arab satellite television broadcasters beamed out largely straightforward, nonstop live coverage from outside the hospital where Sharon – a particularly despised figure among many Arabs – struggled for his life.

A radical Palestinian leader in Damascus, the Syrian capital, called the stroke a gift from God.

“We say it frankly that God is great and is able to exact revenge on this butcher. … We thank God for this gift he presented to us on this new year,” Ahmed Jibril, leader of the Syrian-backed faction Popular Front for the Liberation of Palestine-General Command, a small radical group, told The Associated Press.

Enemies warned

Speaking to reporters outside the hospital, Sharon aide Raanan Gissin warned Israel’s enemies: “To anyone who entertains any notion to try and exploit this situation … the security forces and IDF (Israeli military) are ready for any kind of challenge,” he said.

But a Palestinian commentator on the Saudi-owned Al-Arabiya network offered Sharon unexpected praise as “the first Israeli leader who stopped claiming Israel had a right to all of the Palestinians’ land,” a reference to Israel’s recent withdrawal from the Gaza Strip.

“A live Sharon is better for the Palestinians now, despite all the crimes he has committed against us,” Ghazi al-Saadi said.

Sharon’s physician said early today that he expects Sharon to emerge from surgery “safely.”

“The prime minister is currently in surgery, it is proceeding properly,” Dr. Shlomo Segev said. “We need to wait patiently. I expect him to emerge from it safely.”

Sharon was put in an ambulance at his ranch in the Negev Desert after complaining of feeling unwell. The stroke happened during the hourlong drive to Hadassah Hospital, Dr. Shmuel Shapira told Channel 10 TV.

Doctors checking Sharon late last month said he weighed 260 pounds at the time of the first stroke but had since lost more than six pounds and was otherwise in good health. Sharon is about 5 foot, 7 inches.

The prime minister had been taking blood thinners since the first stroke to prevent another clot, but such drugs also raise the risk of cerebral hemorrhages, which account for only about 10 percent of strokes. Other possible causes are ruptured blood vessels, an aneurysm, or bulge in a vessel wall that bursts, or even chronic high blood pressure.

Cabinet Secretary Yisrael Maimon said Sharon’s authority was transferred to Olmert because the prime minister was under general anesthesia. Under Israeli law, he will serve as acting prime minister until Sharon can resume his powers.