Local media reported that the Nobel laureate and former statesman is in serious condition
Israel's elder statesman Shimon Peres suffered a stroke on Tuesday and doctors put him in an induced coma in hospital, his office said in a statement.
Peres, who is 93, was admitted to Sheba Medical Centre at Tel HaShomer in Ramat Gan "after suffering a stroke," the statement said.
The last of Israel's founding fathers, Peres has held nearly every major office in the country, including prime minister twice and president from 2007 to 2014.
"Former president Peres' doctors sedated and intubated him so as to best facilitate the continuation of his treatment," it said.
"He will undergo a CT scan so as to get a full and updated assessment of his situation."
Speculation mounted over his condition late Tuesday in Israel, with local media reporting that he was in serious condition.
Prime Minister Benjamin Netanyahu had spoken with the director of the hospital, Israel's largest, to receive an update on Peres's condition, a spokesman said.
"The prime minister conveyed the prayers of the entire nation for a quick recovery," his office said.
Opposition leader Isaac Herzog also wished the elder statesman a rapid recovery.
In January, Peres was hospitalised twice for heart trouble.
Peres shared the Nobel Peace Prize with Israel's late prime minister Yitzhak Rabin and late Palestinian leader Yasser Arafat for a 1993 interim peace deal that they and their successors failed to turn into a durable treaty.
When a far-right Jewish Israeli opposed to the peace deal shot dead Rabin in November 1995, Peres became prime minister. Polls showed him way ahead of rightist Likud leader Netanyahu in a campaign for the 1996 election.
But Palestinian suicide bombings that killed dozens of Israelis and an aggressive campaign by Likud battered Peres's rating and he lost the election to Netanyahu by less than 30,000 votes.
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 19 January, 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 told reporters.
He once confided that the secret to his longevity was daily gymnastics, eating little and drinking one or two glasses of good wine.
He once hawkishly rejected any compromise with Arab states, but said he was converted after 1977, when Egyptian president Anwar Sadat made a historic visit to Jerusalem, leading to the first Arab-Israeli peace treaty.