LAUSANNE, Switzerland (AP) -- Veteran Olympic official Mario Vazquez Rana of Mexico resigned all of his positions on Thursday, including a seat on the IOC executive board.
"It has been very difficult for me to take such a drastic decision," he said in a four-page resignation letter released in Mexico that criticized officials who sought to succeed him leading the worldwide group of national Olympic committees.
Vazquez Rana celebrates his 80th birthday in June and is required by IOC age rules to give up his executive seat in July, at the session in London, and his 21-year membership at the end of the year. He did not attend meetings of the 15-member IOC executive leadership in Lausanne this week.
He gives up the presidency of the Olympic Solidarity Commission, which allocates grants to help athletes from smaller nations compete at the games.
Vazquez Rana also will relinquish control of the 204-member Association of National Olympic Committees, which he has led since founding it in 1979.
However, he faced a possible revolt at the ANOC General Assembly in Moscow next month, when some delegates were expected to seek his ouster.
Vazquez Rana angered some international sports leaders last week in Mexico City, where he blocked a secret ballot to be re-elected by acclaim to another four-year term as president of the Pan American Sports Organization.
He had two years remaining on his ANOC presidential term that granted him his IOC executive seat, and which he sought to have extended through 2014. ANOC has selected Irish official Patrick Hickey to take the influential IOC position.
In the most impassioned sections of his resignation note, Vazquez Rana denounced an "outrageous and aggressive race for my succession" at ANOC.
"I have decided to take the only responsible, serious and honorable road: RESIGN, resign for love and respect to sport, to ANOC, to the NOCs and the Olympic Movement," he wrote.