Former Israeli Prime Minister Ariel Sharon, who has been in a coma for the past six months, has been taken to an emergency room.
Sharon: In a coma since January
The Sheba hospital near Tel Aviv said Mr Sharon, 78, was being treated with antibiotics and was having fluids drained from his body.
Doctors said his condition had deteriorated seriously at the weekend.
But a spokesman said his condition had remained stable since then and his brain condition had not changed.
Mr Sharon fell into a coma after a massive brain haemorrhage in January.
He was moved from Jerusalem's Hadassah hospital in May to a specialist centre for long-term care.
His deputy, Ehud Olmert, assumed his powers in January before being elected prime minister in March.
Mr Sharon has been a giant of Israeli politics, holding a number of cabinet positions before he became prime minister in 2001.
As defence minister in 1982, he masterminded the Israeli invasion of Lebanon, but it led to his temporary sidelining in politics.
Without explicitly telling Prime Minister Menachem Begin, he sent the Israeli army all the way to Beirut, a strike which ended in the expulsion of Yasser Arafat's Palestine Liberation Organisation (PLO) from Lebanon.
The move stopped the PLO using Lebanon to launch attacks against Israel, but also resulted in the massacre of hundreds of Palestinians by Lebanese Christian militiamen in two Beirut refugee camps under Israeli control.
Mr Sharon was removed from office in 1983 by an Israeli tribunal investigating the 1982 Lebanon invasion, finding him indirectly responsible for the killings.