Ana Guevara of Mexico after winning the 2007 Pan American title in the 400m

Former world 400 meters champion and 2004 Olympic silver medalist Ana Guevara has retired from track and field after recently denouncing corruption in the Mexican Athletics Federation.

Guevara, considered Mexico's greatest athlete ever, made the announcement at a news conference Wednesday. She said that she was retiring because of problems she faced in 2007, when she requested the removal of Mexican Athletics Federation head Mariano Lara.

The 30-year-old said she could not be part of the Mexican delegation and stay true to her beliefs. Mexico's National Sports and Culture Commission is investigating Lara for mismanagement of funds. However, track and field's world governing body has endorsed him.

Guevara said she was disillusioned with the system in Mexico, but still would like to run for her country. She said she did not want to run in the Beijing Games without a country.

Guevara won the silver medal in the 400 meters in Athens four years ago. She captured the 2003 world championship in Paris. The Mexican finished third in the 400 meters in 2001 and 2005. Last year in Osaka, Japan, she finished fourth behind controversial British runner Christine Ohuruogu, who was allowed run to shortly after serving a one-year ban for missing out-of-competition dope tests.

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