Sharon fights for life after stroke Power transferred to Israel's deputy prime minister RELATED YOUR E-MAIL ALERTS Ariel Sharon Israel or or Create Your Own JERUSALEM (CNN) -- Israeli Prime Minister Ariel Sharon was in "serious" condition and was expected to undergo several more hours of brain surgery after suffering a major stroke, a hospital official said Thursday morning. Sharon underwent about six hours of surgery that initially appeared to stop the bleeding in his brain, said Shlomo Mor-Yosef, the director of Jerusalem's Hadassah Ein Kerem Hospital. But a subsequent brain scan revealed more bleeding and resulted in Sharon being taken back to the operating room, Mor-Yosef said. "We are now continuing with the same operation, there being additional areas that have to be treated," he told reporters just before 7 a.m. (midnight ET). Sharon also was being treated with drugs to try to stop the bleeding in his brain, the doctor said. With Sharon in surgery, under anesthesia and on a respirator, his powers were transferred to Deputy Prime Minister Ehud Olmert, a key ally who followed Sharon in bolting from the Likud bloc to form a new centrist party and shake up Israeli politics. Sharon's stroke plunged the country into political uncertainty less than three months before a pivotal election. Sharon, 77, was taken by ambulance Wednesday night from his home in the Negev Desert, in southern Israel, to the hospital after complaining of chest pain and weakness, according to his senior adviser, Ra'anan Gissen. He arrived at the hospital shortly before 11 p.m. (4 p.m. ET), said Ron Krumer, a hospital spokesman. Israeli Channel 2 reported Sharon was brought in on a stretcher. Doctors sedated Sharon and performed a magnetic resonance imaging scan, Gissen said. They diagnosed a cerebral hemorrhage, or bleeding from a blood vessel in Sharon's brain, and he was taken into surgery to repair the rupture. The procedure lasted six hours. Emerging from the hospital during the initial surgery, Gissen told CNN that "the operation is progressing well. He's in stable condition." Cabinet Secretary Israel Maimon told reporters that after consultations with Olmert and Attorney General Menachem Mazuz, the decision was made to transfer Sharon's powers to Olmert when it became clear the prime minister would have to be sedated for treatment. Olmert and the rest of the Cabinet are to meet Thursday at 9 a.m. (2 a.m. ET), the prime minister's office said. The stroke was the second suffered by Sharon in less than a month. After the first stroke, on December 18, the prime minister was placed on blood-thinning medication, which can be associated with an increased risk of brain hemorrhage. Though Sharon briefly experienced difficulty in speaking after the initial stroke, his doctors then predicted he would recover fully. Sharon's second stroke came after a full day of meetings, though he had trimmed his workload since December 18, Gissen told CNN. The prime minister had been scheduled to undergo minor surgery Thursday to repair a small hole in his heart, which doctors said contributed to a blood clot that caused the first stroke. (Full story) Nicknamed "The Bulldozer" for his stamina during meetings and long working hours, the overweight Sharon had not been in ill health prior to the initial stroke. He is twice widowed, has two sons and lives alone. Political uncertainty A former army general and larger-than-life personality in Israel, Sharon was first elected prime minister in 2001 and re-elected in 2003. (Timeline) He has been seeking a third mandate in the March election, a vote seen as a test for his controversial decision to turn over Gaza and parts of the West Bank to Palestinian control and dismantle Israeli settlements. Sharon faced strong opposition to the disengagement plan within the right-wing Likud bloc he helped found. He decided in November to abandon his political home of three decades and form a new party, Kadima, in an effort to capture the center of the Israeli electorate, where support for his peace initiative is stronger. Polls taken after the prime minister's move showed Kadima vaulting into the lead. However, the party is so closely associated with Sharon that his health problems are likely to inject significant uncertainty into the campaign. Olmert, 60, became Sharon's deputy prime minister in 2003 after serving 10 years as mayor of Jerusalem. (Biography) He took on the additional post of finance minister last year after Sharon's longtime rival within Likud, former Prime Minister Benjamin Netanyahu, resigned to protest the Gaza pullout. In December, Likud members picked Netanyahu to lead them into the March campaign. In Washington, President Bush issued a statement saying he and first lady Laura Bush were "praying for his recovery." "Prime Minister Sharon is a man of courage and peace," Bush said. "On behalf of all Americans, we send our best wishes and hopes to the prime minister and his family." The two leaders have known each other since Bush was governor of Texas and had formed a close political bond that included a mutual antipathy toward dealing with Palestinian Authority President Yasser Arafat, who died in 2004. Sharon's health problems also cast a shadow over Palestinian parliamentary elections scheduled for January 25. Palestinian leader Mahmoud Abbas this week threatened to cancel the vote unless Israel reverses a decision to bar Palestinians from voting in Jerusalem. The Palestinian Authority has struggled to gain control over Gaza since Israel completed its withdrawal in September. Days of unrest in Rafah continued Wednesday, as gunmen stole heavy machinery and demolished part of a wall separating Gaza and Egypt. (Full story) Questions have grown over how well the ruling Fatah party will fare in the elections, in which it will be pitted against the Islamic militant group Hamas and other organizations. Outside the hospital in Jerusalem, Gissen said Israel's government is functioning fully and that security forces are prepared to handle any potential threat. "This is not the right time to mess with us," he told CNN. CNN's Dana Bash and John Vause contributed to this story. Home Page Get up-to-the minute news from CNN CNN.com gives you the latest stories and video from the around the world, with in-depth coverage of U.S. news, politics, entertainment, health, crime, tech and more. Home Page Get up-to-the minute news from CNN CNN.com gives you the latest stories and video from the around the world, with in-depth coverage of U.S. news, politics, entertainment, health, crime, tech and more.