Marathon world record holder Haile Gebrselassie says he won't compete in the Olympic marathon because of fears that Beijing's air pollution would damage his health.

The Ethiopian runner, who suffers from asthma, said he would still compete in the shorter 10,000 metres event in the August Games.

"The pollution in China is a threat to my health and it would be difficult for me to run 42 km in my current condition," he told Reuters by telephone.

"But I am not pulling out of the Olympic event in Beijing all together. I plan to participate in the 10,000 m event," he added.

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