The condition of former Israeli prime minister Ariel Sharon, who has been in a coma since January, has deteriorated in the past two days, doctors caring for him said yesterday.

Doctors at the Tel Hashomer hospital near Tel Aviv said Mr Sharon, 78, who fell into a coma after a stroke on January 4, was suffering from an accumulation of fluids in his body and problems with the functioning of his kidneys.

"Over the past two days the doctors have identified a deterioration in the kidney function...and changes in brain tissue," a statement issued by the hospital said.

"The doctors are continuing tests in order to diagnose the changes which have taken place in Mr Sharon's body and to administer the appropriate treatment."

Mr Sharon's family was with him, the hospital said.

The worsening of Sharon's health comes as Israeli forces battle Hizbollah guerrillas in southern Lebanon, following the capture of two Israeli soldiers by guerrillas on July 12 and the bombarding of northern Israel by Hizbollah rockets.

Ariel Sharon, a former general, was Israel's defence minister when the country last invaded Lebanon, in 1982, an operation that was to result in a lengthy occupation that only ended in 2000.

After his haemorrhagic stroke, Mr Sharon underwent several brain operations but has never regained consciousness. In May, he was moved from a Jerusalem hospital to Tal Hashomer, a long-term care facility. Mr Sharon's deputy, Ehud Olmert, took over as interim leader when Mr Sharon fell ill.

Mr Olmert formally assumed office after the Kadima party that Mr Sharon founded won the most seats in elections earlier this year and established a governing coalition.

For decades, Mr Sharon was a key figure in shaping the Middle East. Regarded as an archetypal hawk, he was a champion of the settler movement that involved building Jewish communities on occupied Palestinian land.