Scott Blackmun, the CEO of the United States Olympic Committee, stepped down unexpectedly Wednesday.

The USOC cited "ongoing health issues resulting from prostate cancer" as the reason for the immediate resignation. Current board member Susanne Lyons will serve as acting CEO until the position is filled.

The resignation comes days after the Winter Olympics came to an end and in the wake of an investigation into the Larry Nassar sexual abuse scandal that shook USA Gymnastics.

"Given Scott's current health situation, we have mutually agreed it is in the best interest of both Scott and the USOC that we identify new leadership so that we can immediately address the urgent initiatives ahead of us," USOC chairman Larry Probst said in a statement released by the USOC.

"The USOC is at a critical point in its history. The important work that Scott started needs to continue and will require especially vigorous attention in light of Larry Nassar's decades-long abuse of athletes affiliated with USA Gymnastics. We will be working with key stakeholders to help identify a permanent successor to Scott. In the meantime, I am confident that Susanne is the right person to help us navigate this critical transition period."

Blackmun, 60, became the CEO in 2010 and saw success in the position, including securing the United States as the host of the Olympic Games in 2028. He was not able to attend the Winter Olympics in Pyeongchang due to the health issues he is facing.

"Serving the USOC and its many stakeholders and working with our board, our professional staff and many others who support the Olympic and Paralympic movements has not only been immensely rewarding, it has been an honor and the highlight of my professional life," he said in a statement. "I am proud of what we have achieved as a team and am confident that Susanne will help the USOC continue to embody the Olympic spirit and champion Team USA athletes during this transition."

The USOC announced Blackmun's resignation at the same time the committee revealed new plans to "protect athletes," which includes ensuring athletes have a stronger voice and increased funding for internal investigations.