Joey Cheek (file photo)

The United States is formally protesting China's decision to deny a visa to U.S. Olympic gold medalist and Darfur anti-violence campaigner Joey Cheek.

White House spokeswoman Dana Perino said Wednesday the U.S. is disturbed to learn that China has refused his visa.

Cheek, a speedskater who competed in the 2006 Winter Olympics, had planned to go to Beijing to support Olympic athletes who are members of Team Darfur. The group aims to call attention to the humanitarian crisis in Sudan's Darfur region.

China is a major investor in Sudan and has come under increasing pressure to help end the violence in Darfur.

International experts say more than 200,000 people have died and some 2.5 million have been displaced from their homes since Darfur rebel groups rose up against the Sudanese government in 2003.

Sudan says Western governments and media have exaggerated the scale of the conflict.

Some information for this report was provided by AFP, AP and Reuters.