Rotstein said the Shin Bet security service were securing the hospital and that the long-term security arrangements for Sharon would not interfere with other patients there.

Sharon was Israel's most popular politician, and the country was stunned to see the man, who for decades personified Israel's military might, felled by illness.

His stroke came after Sharon saw through his contentious plan to withdrawal Israel from the Gaza Strip after 38 years, and just two months after Sharon shook up the Israeli political map by bolting his hardline Likud Party to form the centrist Kadima faction.

With Sharon as its leader, Kadima was expected to easily win Israeli elections. After the stroke, Sharon's successor as party leader, Prime Minister Ehud Olmert, led Kadima to a slim victory in the March 28 vote.

Olmert has painted his plan to withdraw Israel from much of the West Bank, solidify its hold on major settlement blocs and unilaterally draw the country's borders in the coming years as a continuation of Sharon's "disengagement plan," which began with the Gaza withdrawal.

Sharon had a small stroke in December and was put on blood thinners before he suffered a severe brain hemorrhage in January. The Israeli leader underwent several, extensive brain surgeries to stop the bleeding, and many independent experts doubted that he would ever recover.

The last surgery on Sharon, in April, was to reattach a part of his skull, removed during the emergency surgery to reduce pressure on his brain. The reattachment was described as a necessary step before transferring Sharon to a long-term care facility.

Sheba had a wider range of rehabilitation treatments than Hadassah, including physiotherapy and hydrotherapy, Rotstein said.

"The experts are saying that his chances of waking up are not good. But we prefer to hope for the best, even though they say the likelihood is low, we will do the maximum to revive him," he told reporters.

Dr. Moti Ravid, an outside medical expert, told Israel's Army Radio that there was no hope of Sharon awakening from his coma.

"It's not a nice thing to say, because people say that as long as a person is alive there is still hope, but there is no chance that he will wake up," he said. "He still doesn't breathe by himself. That means the central respiratory center in his brain is in an irreversible condition so all the talk about rehabilitation are empty words."