An emergency operation on Israeli Prime Minister Ariel Sharon has stopped bleeding in his brain, but he remains in a critical condition, doctors say.
Mr Sharon's illness throws Israeli politics into turmoil
A scan after the operation showed "significant improvement" in his brain, Hadassah hospital director Shlomo Mor-Yosef said.
Mr Sharon, 77, had already undergone seven hours of surgery on Wednesday night after suffering a massive stroke.
His deputy, Ehud Olmert, has taken over as caretaker prime minister.
Scheduled elections are to go ahead in March.
Former Israeli Prime Minister Ehud Barak told the BBC after the latest operation that Mr Sharon was in the final days or hours of his life.
But Felix Umansky, a leader of the surgical team working on the prime minister, told the AFP news agency there was still a chance he could recover.
The BBC's Middle East editor Jeremy Bowen says Israelis are experts at soaking up emergencies, but the loss of Mr Sharon from politics is a highly significant moment in this country's history.
Mr Mor-Yosef announced on Friday evening that the latest operation had successfully released pressure on Mr Sharon's brain.
"There is no active bleeding and the intracranial pressure has returned to normal," he said.
Earlier in the day he had said Mr Sharon was returning to the operating theatre because a scan had showed an enlarged ventricle.
Surgeons would drain excess blood to relieve the pressure, he said.
An increase in pressure inside the skull can be a severe medical problem.
The BBC's Jon Leyne in Jerusalem says the new operation was unexpected.
Earlier, the doctors were saying they expected no change in Mr Sharon's condition before the weekend, and that they planned to keep him sedated in an "induced coma" at least until Sunday.
After the latest operation, the hospital reiterated that they would keep Mr Sharon under sedation until Sunday.
ARIEL SHARON'S HEALTH
Sharon suffers minor stroke on 18 December 2005
Doctors discover small hole in heart, schedule operation for 5 January
Sharon rushed to hospital one day before scheduled surgery with major stroke
Undergoes two operations overnight on 4/5 January, followed by third on 6 January
"The goal of the sedation is to lower the oxygen needs of the brain and to allow the brain ... to rest," Hadassah hospital deputy director Shmuel Shapira told the Israeli daily Haaretz.
"So certainly until Sunday, and it's possible beyond that, he will be sedated."
Mr Sharon's sons, Omri and Gilad, are among the family members and aides who have gathered at the Hadassah hospital in Jerusalem.
US Secretary of State Condoleezza Rice has cancelled a planned six-day trip to Indonesia and Australia in light of the situation in the Middle East, a spokesman said on Friday.
She is reported to have spoken to Mr Olmert by phone on Friday.
Correspondents say aides to Mr Sharon assume he will not be capable of resuming work.
As head of the recently formed Kadima (Forward) party, Mr Sharon had been widely expected to win Israel's general election on 28 March.
However, a survey published by Israel's Yediot Ahronot newspaper on Friday said Kadima led by Mr Olmert would still win 39 of the Knesset's 120 seats, with Labour capturing 20 seats and Likud 16.
Mr Olmert held talks with Kadima colleague Shimon Peres, a rival-turned-ally of Mr Sharon, on Friday morning.
Mr Peres said he was "very worried" about the prime minister's health.
But, he said, "We will know how to continue Israel's policy... to continue Ariel Sharon's policies."