Israeli ex-president and Nobel Peace Prize winner Shimon Peres was "fighting for his life" on Tuesday, two weeks after suffering a stroke, a source close to the veteran statesman said.
Peres has been in hospital near Tel Aviv since September 13, when he was admitted feeling unwell and suffered the stroke with internal bleeding.
Israel has been on edge over the health of its last remaining founding father, who has been under sedation and respiratory support in intensive care.
The 93-year-old has held nearly every major office in the country, serving twice as prime minister and also as president, a mostly ceremonial role, from 2007 to 2014.
"The president is fighting for his life," the source told AFP, speaking on condition of anonymity.
"His health position is very, very difficult. His doctors are worried about his health."
The source said later that family members were at the hospital.
A spokeswoman for Sheba Medical Centre at Tel Hashomer, where Peres is being treated, was more cautious in describing his current state, but called his condition "very, very serious".
"The brain damage is permanent," the spokeswoman, Lee Gat, told AFP.
Prominent visitors arrived at the hospital on Tuesday, including Interior Minister Aryeh Deri and opposition leader Isaac Herzog, the head of Labour, Peres's longtime party.
"We continued to pray and hope, but we have also heard about his severe and deteriorating condition, and we all pray," Deri told dozens of journalists gathered at the hospital.
"For someone who has known Shimon for 30 years, it is hard to see -- hard to see that he is quiet, as we are used to a very vital, very active Shimon."
Peres won the 1994 Nobel Peace Prize jointly with prime minister Yitzhak Rabin and Palestinian leader Yasser Arafat for his role in negotiating the Oslo Accords, which envisioned an independent Palestinian state.
The former hawk turned dove is widely respected both in Israel and abroad.
After suffering the stroke, he received an outpouring of support from across the world, including from Pope Francis, US President Barack Obama, the Clinton family, Donald Trump, Britain's ex-premier Tony Blair and Russian President Vladimir Putin.
UN Secretary General Ban Ki-moon has said he was hoping Peres made a "swift and full recovery", calling him "tireless in seeking peace between Israelis and Palestinians".
Signup to our newsletter and follow us on Facebook and Twitter!
- Previous heart troubles -
There had been signs of improvement last week.
On September 18, Peres's office said doctors planned to gradually reduce his sedation and respiratory support to judge his response.
His personal physician and son-in-law Rafi Walden had said at the time that Peres had seen "very slow, moderate improvement".
On Tuesday, Walden declined to comment in detail, saying only that his condition was "severe".
In January, Peres was hospitalised twice because of heart trouble.
In the first case, the hospital said he had suffered a "mild cardiac event" and underwent catheterisation to widen an artery.
He was rushed to hospital a second time just days later with chest pains and an irregular heartbeat.
Peres has sought to maintain an active schedule despite his age, particularly through events related to his Peres Center for Peace.
When leaving hospital on January 19, Peres said he was keen to get back to work.
"I'm so happy to return to work, that was the whole purpose of this operation," he said.
In March, he met British supermodel Naomi Campbell at his Peres Center for Peace during an event linked to International Women's Day. On the same day, he met visiting US Vice President Joe Biden.
Born in Poland in 1923, Peres emigrated to what was then British-mandated Palestine when he was 11.
He joined the Zionist struggle and met David Ben-Gurion, who would become his mentor and Israel's first prime minister.
Peres became director general of the nascent defence ministry at just 29 years old.
Beyond his accomplishments in the public eye, he was also seen as a driving force in the development of Israel's undeclared nuclear programme.
Peres once confided that the secret to his longevity was daily exercise, eating little and drinking one or two glasses of good wine.