European Athletics President Svein Arne Hansen has suffered a serious stroke and is recovering in hospital, federation chief executive Christian Milz said on Tuesday.
"Doctors have not yet given a detailed prognosis about his recovery, but it is expected that he will remain in the hospital for at least one week and then undergo a significant period of rehabilitation," Milz said in a statement.
Norwegian Hansen, 73, suffered the stroke while at home on Sunday, the statement added.
He was tested for the presence of Covid-19 and tests were negative.
Long active in athletics, Hansen is also a member of the World Athletics Council.
The European Athletics Executive Board will meet by conference call early next week to discuss the sharing of Hansen's duties during his period of incapacity, the statement said.
World Athletics president Sebastian Coe said he was "shocked" by the news and wished Hansen "a speedy and full recovery".
Coe added in a statement: "He is a hugely popular figure in the sport of athletics and has been a passionate advocate of the sport for half a century.
"Our thoughts are with his family, his colleagues and all the athletes he cares so passionately about. We stand by to support European Athletics at this time."
