GOOD NEWS:Sharon back in operating theatreNo other Israeli politician has the political stature of Ariel SharonStricken Israeli Prime Minister Ariel Sharon is undergoing another operation after a scan revealed fresh bleeding in his brain.
Hospital director Shlomo Mor-Yosef said the scan showed an enlarged ventricle and surgeons were trying to drain excess blood to relieve the pressure.
Mr Sharon, 77, underwent a seven-hour operation on Wednesday night after suffering a massive stroke.
His deputy, Ehud Olmert, has taken over as caretaker prime minister.
Induced coma
At 1210 (1010 GMT), Professor Mor-Yosef told reporters Mr Sharon had returned to the operating theatre.
The gravity of Sharon's condition reshuffles all the political cards
Israeli newspaper Yediot Ahronot
Press reflects nation's shockArab media ponder legacyQ&A: Israel's political future "There was an increase in cranial pressure and there were changes in the blood pressure," he said.
"It was decided to bring the prime minister to the operating room in order to deal with these two issues - to drain the bleeding and to decrease the intracranial pressure."
An increase in intracranial pressure can be a severe medical problem.
It can lead to compression of important brain structures and the restriction of blood through the vessels that supply the brain.
The BBC's Jon Leyne in Jerusalem says this new operation is 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" until at least 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
What is a stroke? Correspondents say aides to Mr Sharon are working on the assumption that he will not be capable of resuming work.
Israel's general election due on 28 March will go ahead as planned.
Mr Sharon had recently formed a new political party, Kadima (Forward), after defecting from the right-wing Likud party.
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.
The BBC's Jeremy Bowen says Mr Sharon's stroke changes every political calculation with no-one, including Mr Olmert, commanding such Israeli trust.
Our correspondent says at any rate a successor may not have the will, experience or desire to follow Mr Sharon's plans.
