Chairman of the opposition Isamaa Party Helir-Valdor Seeder was being treated in hospital on Friday after testing positive for coronavirus.
The party's head of communication Karl Sander Kase confirmed to news website Delfi that Seeder, 56, was being treated in hospital and that he had been diagnosed with covid-19.
Kase would not reveal any more information about Seeder's condition but told ERR he had communicated with him on Friday evening.
Asked if the party leader had been vaccinated, Kase said this was sensitive health data. However, at last week's Opinion Festival, Seeder said he had been vaccinated against coronavirus.
Editor: Helen Wright