Reaction to the death of three-times Formula One champion Niki Lauda, who died on Monday at the age of 70:
Jean Todt, FIA (international motorsports governing body) president
"Niki Lauda was a hero of motor sport, who inspired me in my youth. He is a milestone in the history of Formula One. All my thoughts go out to his family, friends and Mercedes-AMG F1 team."
Chase Carey, Formula One chairman and chief executive
"Formula One has lost not only one of the truly great exponents of the sport but also one of its heroes. His love of racing and the courage he demonstrated were simply extraordinary and he inspired so many fans."
Toto Wolff, team principal at Mercedes, where Lauda was chairman
"Niki will always remain one of the greatest legends of our sport - he combined heroism, humanity and honesty inside and outside the cockpit
"His passing leaves a void in Formula One. We haven't just lost a hero who staged the most remarkable comeback ever seen, but also a man who brought precious clarity and candour to modern Formula One.
"He will be greatly missed as our voice of common sense. Our Mercedes team has also lost a guiding light."
Ferrari Formula One team, where Lauda won two world championships
"Today is a sad day for F1. The Ferrari family learns with deep sadness the news of the death of our friend Niki Lauda ... You will remain forever in our hearts and in those of the fans."
Luca di Montezemolo, former Ferrari president
"Your passing leaves an enormous void inside me.
"With you I have lived some of the most beautiful moments of my life, we shared many unforgettable Ferrari victories and we were always bound together by great affection, even when we found each other competing on rival teams."
McLaren Formula One team, where Lauda won his final world championship
"All at McLaren are deeply saddened to learn that our friend, colleague ... Niki Lauda, has passed away. Niki will forever be in our hearts and enshrined in our history."
Damon Hill, former Formula One world champion
"He was one of the few men who could sit down with Enzo Ferrari and Bernie Ecclestone, look them straight in the eye and they knew he meant business. He was a remarkable individual in every way."
Jenson Button, former Formula One champion
"A legend has left us. Rest in peace Niki."
Nico Rosberg, former Formula One champion
"Thank you for everything that you did for me. I learned so much from you.
"Your passion, your fighting spirit, to never give up, your belief that you always meet twice in life, and even your patience with us youngsters.
"Myself and... 100 million fans around the world whom you also so strongly inspired to never give up in the hardest of times are thinking of you and your family... Rest in peace."
Giedo van der Garde, former driver for Caterham F1
"Saddened by the news of Niki Lauda. Not only a huge inspiration with the biggest comeback in sport so far, but a unique personality as well.
"Personally, I'll never forget him sticking up for me in Melbourne after my F1 career ended. Rest in peace, Niki."
Martin Brundle, former Formula One driver
"The man himself is no longer with us. A great human being, determined, relentless, talented, passionate, forthright, honest, humble and great company.
"Living on borrowed time since his awful crash in 1976, he certainly made the absolute most of that gift. RIP Niki."
Andretti Autosport, Indy Car team
"We are deeply saddened to hear of the passing of Niki Lauda. He will forever be remembered as a legend, a friend, advocate for safety in our sport and much, much more.
"Niki will be missed deeply and our sincerest condolences are with his family and friends."