Officials at the hospital near Tel Aviv where Sharon, comatose since a 2006 stroke, has been treated, did not answer their telephones. A Health Ministry spokeswoman declined to comment.

The ex-general and right-wing leader was known for executing a dramatic political about face with a 2005 Gaza pullout that turned Israeli politics on its head when he quit his party and created a centrist faction that ruled Israel for several years.

The radio, echoing reports by other Israeli media outlets, said Sharon's condition had worsened in the past several days and that his life was in danger due to kidney failure.

The Haaretz newspaper's Web site quoting an unnamed source said that Sharon could die in "a matter of days" if his condition continued to decline. Israel's Channel 2 television said Sharon's sons were at his bed side.

Sharon was badly famous for the 1982 massacres of Palestinians at Sabra and Shatila refugee camps claimed the lives of at least 800 civilians.

Outside occupied lands, international human rights groups have long argued that Sharon must be tried for his historical war crimes.