Veteran left-wing politician Manolis Glezos, 97, was admitted to the intensive care unit of the 417 Army Equity Fund Hospital (NIMITS) three days ago.
He has hospitalised for acute respiratory failure, however his condition worsened on Thursday and he was transferred to intensive care.
His condition is viewed as critical.
Glezos is best known for his involvement in Greece’s resistance movement during WWII.
According to popular tradition, on 27 April 1941 Konstantinos Koukidis was ordered to lower the Greek flag, and raise the Nazi swastika flag. Koukidis allegedly lowered the flag, and jumped from the Acropolis holding it, rather than raise the Nazi flag.
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On 30 May 1941 Glezos and Apostolos Santas climbed on the Acropolis and tore down the swastika, which had been there since 27 April 1941, when the Nazi forces had entered Athens.
Glezos has been writing articles in Greek newspapers since 1942 and was the editor of the newspapers Rizospastis and I Avgi in the 1950s. He was awarded the International Award of Journalism in 1958, the Golden Medal Joliot-Curie of the World Peace Council in 1959, and the Lenin Peace Prize in 1963. He has also published six books in Greek: