The 77-year-old Sharon remains in intensive care after suffering massive haemorrhaging, but medics have indicated that his condition is no longer life-threatening.
"The prime minister's condition is serious but there is no immediate danger to the prime minister's life," Sharon's chief anaesthetist Yoram Weiss said at Jerusalem's Hadassah hospital on Tuesday afternoon.
"In recent days there has been a significant change in the prime minister's condition but we still have a long way to go and we all have to be patient.
"Since yesterday the prime minister has been breathing spontaneously. He is on a respirator but he is the one who is operating the respirator," he said.
The hospital's director, Shlomo Mor-Yosef, told the news conference that Sharon had moved his left hand for the first time and had managed to move his right arm more than in an initial stimulus test on Monday.
"These are neurological changes that show a slight progress in the brain function of the prime minister," Mor-Yosef said.
Medics have said only the right-hand side of Sharon's brain, which controls the left side of his body, was affected in the brain haemorrhage and the latest movement may indicate he has retained more brain function than first thought.
Doctors said it would be several days before the sedatives wore off completely and they could start gauging Sharon's ability to think and reason. He has yet to open his eyes.
Doctors feel it is too early to say
whether Sharon would recover
"We have a long way to go and we need to be patient," Weiss said.
Another doctor said when one of Sharon's sons spoke, the prime minister's blood pressure rose. Mozart symphonies were played at his bedside in an effort to elicit a response.
Among the ways doctors hope to stimulate his senses is to place his favourite foods, including a plate of shawarma, a sliced meat dish, in his hospital room, Israel Radio said.
The loss of Sharon, who raised peace hopes by pulling settlers and troops out of Gaza in September after 38 years of occupation, would deepen uncertainty over the future of Middle East diplomacy.
Too much damage
Sharon's surgeons say there is a good chance he will live. But the medical consensus is he has suffered too much damage to ever return to Israeli politics, an arena he has dominated like no figure since David Ben-Gurion, the founding prime minister.
As doctors launched their effort to wean Sharon off his sedation on Monday, Sharon started breathing on his own - though still hooked up to a respirator - and slightly moved his right arm and leg.
"Metaphorically speaking, we have backed five metres away from the edge of the cliff"
Dr Yoram Weiss,
Doctors said they elicited further right-side movement on Tuesday and he also moved his left hand for the first time.
Sharon had been kept in a coma since Wednesday to aid healing after surgery to stop widespread bleeding in his brain.
If doctors declare Sharon permanently incapacitated, they will pass on their finding to Israel's attorney-general. The Israeli cabinet would then elect a prime minister from ministers of Sharon's Kadima party who are also parliamentarians.
Sharon's deputy, Ehud Olmert, 60, already named interim prime minister, would be expected to keep the job in the run-up to the March election.