JERUSALEM — With Prime Minister Ariel Sharon recovering from emergency brain surgery Saturday, his doctors said it was still too early to assess how much damage the Israeli leader has suffered from a massive stroke. Independent experts said the prognosis remained grim.

An official determination on Sharon's condition will likely take place Sunday, when doctors plan to wean him off the drugs that are keeping him in a state they described as a medically induced coma.

Sharon, 77, underwent five hours of emergency brain surgery Friday that doctors said successfully stopped a hemorrhage and relieved swelling inside his skull. Although doctors reported "significant improvement" after the surgery, Sharon remained in serious condition.

Hadassah hospital spokesman Ron Krumar said Saturday there had been no change in the prime minister's condition. He was taken for a brain scan Saturday morning, which was a planned procedure, Krumer said. No further details were immediately available.

Sharon suffered the stroke, his second in less than three weeks, late Wednesday, throwing the country into turmoil. His deputy, Ehud Olmert, was quickly named the acting prime minister.

Olmert took calls from Secretary of State Condoleezza Rice and Egyptian President Hosni Mubarak on Friday, a sign that the Israeli government was moving ahead without its hard-charging leader.

Key members in Sharon's Kadima Party said they would rally around Olmert, easing concerns that the movement, founded by Sharon two months ago, might fracture in his absence. A new poll showed Kadima emerging victorious in March 28 elections under Olmert's leadership.

Synagogues across the country were expected to mention Sharon by name in the special prayer for the ill recited in services Saturday morning.