Austrian President Thomas Klestil (search) was in critical condition Monday after being rushed to hospital following heart failure.

Security guards at Klestil's suburban Vienna (search) home used a defibrillator to revive the president early Monday and he was flown by helicopter to Vienna's General Hospital, the Austria Press Agency reported.

APA quoted hospital spokeswoman Karin Fehringer as saying Klestil, 71, was in "critical condition."

Presidential spokesman Meinhard Rauchensteiner told The Associated Press: "He is being treated at the hospital and it is serious."

Klestil's term ends Thursday, when Heinz Fischer takes over as president. Chancellor Wolfgang Schuessel (search) was temporarily taking over the presidential duties because of Klestil's illness, APA reported.

Klestil suffered from a severe case of pneumonia in 1996, and his lung problems turned serious again in recent days.

While the post is mostly ceremonial, the Austrian president is commander-in-chief of country's tiny military, and the constitution gives the president the power to reject nominations for Cabinet ministers or even to remove them from office -- something that has rarely been done.