Ariel Sharon has a respiratory infection that has forced doctors to delay surgery on the comatose Israeli leader, the hospital caring for him said Tuesday.

Sharon, 78, was to undergo surgery Tuesday to reattach a portion of his skull removed after his Jan. 4 stroke.

Jerusalem's Hadassah Hospital said the operation was delayed "due to a slight infection discovered this morning in his respiratory tract." It was being treated with antibiotics.

The surgery, which would have been Sharon's eighth since his stroke, is routine for people in his condition, but does involve risk, said hospital spokesman Ron Krumer.

"There is no surgery without risks. The minute that you treat a person, and especially in his head, there are risks," Krumer said.

He said doctors would not operate until the infection is gone.

"There are no rules to how long it could take to go away. It could take one day, it could take two days, it could take two weeks," Krumer said.

Israel's Army Radio described the skull surgery as the last step before Sharon is moved to a long-term care facility. Sharon has been at Hadassah since the stroke.

Krumer refused to confirm the report, but experts in long-term care have examined Sharon in recent weeks.

The stroke suddenly removed the popular prime minister from Israel's political landscape, shortly after he formed the centrist Kadima Party. The stroke shocked Israelis, many of whom believed the ex-general would bring them a more secure future.

Kadima won last week's Israeli election, although by a smaller margin than was expected when Sharon headed the movement. Analysts have said the party's popularity was a result of Sharon's legacy.