China's 110 metre hurdles Olympic champion Liu Xiang officially announced his retirement on Tuesday on Sina Weibo, China's version of social networking site Twitter.
Liu became China's first male Olympic champion in athletics when he won the 110m hurdles at the 2004 Games, equalling Briton Colin Jackson's world record of 12.91 seconds. Three years later he won a world championship gold in Osaka, Japan, reports Xinhua.
He earlier expressed his decision to retire last Friday.
Liu bettered the world record to 12.88 seconds in Lausanne, Switzerland, in July 2006. Aries Merritt of the United States of America is current world record holder iat 12.80 seconds.
At the 2008 Beijing Games, Liu limped off in a first-round heat with an aggravated achilles tendon injury following another runner's false start.
Four year later at London Olympics, Xiang pulled out of competition again with a similar complaint.