THE HAGUE, June 14 -- Former UCI president and IOC member Hein Verbruggen died at the age of 75 on the night of Tuesday to Wednesday after a long battle against leukemia, Dutch media report on Wednesday.

The Dutchman was the president of the UCI (Union Cycliste Internationale), the world cycling governing body, between 1991 and 2005. After his retirement, he was appointed honorary chairman, a position he had until his death.

During his reign as UCI president, cycling got more professional. But he was criticized for not acting tough on doping sinners, especially on Lance Armstrong, who would later be stripped from his seven Tour de France titles.

Brian Cookson, current UCI President, expressed his condolences through Twitter. "I am sad to hear of the passing of Hein Verbruggen and offer my sincere personal condolences to his family and friends," he wrote.

After his departure as UCI president, Verbruggen played a big role in the organization of the Beijing Olympic Games in 2008 as member of the International Olympic Committee IOC, a function he had from 1996 until 2008.

"Hein Verbruggen lives on in my memory as a man with a big heart for the Olympic movement, cycling and for the people around him," Dutch King Willem-Alexander, member of the IOC from 1998 until 2005, said in a statement."

"Hein Verbruggen was a fearless fighter for his sport," said IOC President Thomas Bach. "Thanks to his great engagement and his management skills. He greatly contributed to the success of the Olympic Games of Beijing in 2008 as Chair of the Coordination Commission. For that he will always be remembered."