Former Israeli President Shimon Peres suffered a "major stroke" on Tuesday and experienced heavy bleeding in the brain, a hospital official said, as doctors raced to stabilize the 93-year-old Nobel laureate.
Dr. Itzik Kreiss, director of the Sheba Medical Center, told reporters outside the hospital near Tel Aviv that Peres experienced "lots of bleeding" as a result of the stroke. He said that he had undergone a battery of tests, and that doctors planned to hold another assessment in a few hours.
Standing alongside Kreiss, Peres' son Chemi said that the situation was "not simple," but that the family was trying to stay positive.
"My father is very special. I am keeping optimistic, hoping for the best. But these hours are not easy," he said.
He thanked the Israeli public for offering its support and prayers.
Peres is the elder statesman of Israeli politics and the last surviving link to the country's founding fathers.
Over a seven-decade career, he held virtually every senior political office in Israel, including three terms as prime minister and stints as foreign and finance minister. He won the 1994 Nobel Peace Prize for his work in reaching an interim peace agreement with the Palestinians.
He had remained active since completing his seven-year term as president in 2014, and had even uploaded a video to his Facebook account earlier in the day.
In the video , in which Peres encourages the public to buy locally made products, he appears somewhat weary but is otherwise alert and coherent. Channel 10 said Peres had also delivered an hourlong lecture earlier in the day.
Earlier this year, Peres was twice hospitalized for heart problems but quickly released. His office said Peres received a pacemaker last week.
As president, a largely ceremonial office, he cultivated an image as the country's elder statesman and became one of its most popular public figures.
He also became a fixture at international conferences like the World Economic Forum in Davos. Earlier this month, he participated in the Ambrosetti Forum in Cernobbio, Italy.
Since leaving the presidency, Peres frequently hosted public events at his peace center, bringing together Arabs and Jews in efforts to promote coexistence.
In a message posted on Facebook, Prime Minister Benjamin Netanyahu wished Peres a speedy recovery. "Shimon, we love you and the entire nation wishes you get well," he said.
2 p.m.: This article has been updated with comments from the hospital director.
12:45 p.m.: This article has been updated with an Israeli officials saying that Peres has undergone a CT scan.
11:10 a.m.: This article has been updated with news that Peres was placed on a respirator.
11 a.m.: This article has been updated with additional details and comments.