Israel's cabinet has signalled a formal end to Ariel Sharon's premiership three months after he suffered a stroke.
Ariel Sharon has been in a coma since January
Ministers voted unanimously to declare him "permanently incapacitated", which promotes Ehud Olmert from the position of acting PM to the full premiership.
Mr Olmert is currently forming a coalition government after the centrist Kadima party won elections last month.
Mr Sharon, 78, founded Kadima weeks before suffering a severe stroke on 4 January, which left him in a coma.
He has never regained consciousness and has been lying in hospital in Jerusalem where he has had numerous operations.
BBC correspondent Jon Leyne in Jerusalem says the decision is only a formality in practice, and Mr Olmert's responsibilities will not change.
Our correspondent says Israeli politics has already moved on.
There has been little public reaction to the news of Mr Sharon's political passing. Israelis are now waiting to see how Mr Olmert puts into practice the policies initiated by Mr Sharon.
Mr Olmert, 60, was given six weeks to form a new government after Kadima came first in Israeli elections on 28 March.
However, Tuesday events mark the end of the career of one of the most influential figures in Israeli history, our correspondent says.
"This is a very difficult and sad day for all of us," said government secretary Yisrael Maimon.
"We offer our prayers and best wishes to the prime minister, his family and his friends for his recovery," Mr Maimon added.
The decision to declare Mr Sharon unable to hold office will come into effect 100 days after he was declared "temporarily incapacitated" by Israel's attorney general.
ARIEL SHARON'S HEALTH
18 Dec 2005: Sharon suffers minor stroke
4 Jan 2006: Sharon rushed to hospital one day before scheduled heart surgery with major stroke
4/5 Jan: Undergoes two operations overnight
6 Jan: Third round of surgery
9 Jan: Doctors start to try to rouse him from medically induced coma
15 Jan: Has tracheotomy to help to wean him off respirator
1 Feb: Doctors insert feeding tube into stomach
11 Feb: Has infected area of colon removed after condition worsens
5 April: Has part of skull repaired
Under Israeli law, a sick prime minister can only have a temporary replacement for that length of time, before a permanent successor must be named.
The cabinet vote was taken early as the week-long Passover holiday begins on Wednesday. Mr Olmert will formally become full prime minister on 14 April.
Our correspondent says it seems that political considerations may have delayed the Israeli cabinet from acknowledging the inevitable.
Even in a coma, Mr Sharon was a key figure in the election campaign of Kadima. His picture was at every rally and old recordings of his voice were even used in some of the party's election advertisements.
'Critical but stable'
Mr Sharon's condition remains "critical but stable" according to a spokeswoman at the Hadassah Hospital. She said there were no plans for further surgery, and no plans to move him.
Mr Sharon has been prime minister since March 2001.
Once a darling of right-wing nationalist Israelis, he adopted a policy of unilateral disengagement from the Palestinians, under which he uprooted settlers and the troops who protected them from Israeli-occupied land.
The unexpected step was popular among most Israelis, but it split Mr Sharon's ruling Likud party and forced him to leave and form the new Kadima party.