China's star hurdler Liu Xiang said he knew before Monday's ill-fated heat that his foot would fail him and that he had no choice but to pull out.

In his first public remarks since he hobbled from the Bird's Nest stadium on Monday, Liu said in a state television interview broadcast on Tuesday that he "never spoke of failure lightly", the China News Service reported.

• Images: Track and Field

Liu was the host nation's best hope of an athletics gold medal at the Olympics [Images] and his pained withdrawal from the 110m hurdles startled this country where his image hangs on countless billboards.

He said he didn't feel right when warming up for the race.

"I knew my foot would fail me. I felt painful when I was just jogging," Xinhua news agency quoted hims as saying.

"So many people have been worried and caring about me. I feel sorry. I could do nothing but pull out of the race...

"I didn't know why things turned out this way. I wanted to hang on. But I couldn't. It was unbearable. If I had finished the race, I would have risked my tendon. I could not describe my feeling at that moment."

He said he was not the type of person to quit and that he would be back.

"There'll be opportunities next year, and afterwards there'll still be opportunities. After all, I'm still in peak condition. I need to be a bit optimistic and can't grumble and blame others."

China's leaders have thrown their support behind Liu Xiang, urging him to overcome injury and return to "glory".

In a sign of the national prestige invested in the hurdler, Chinese Vice President Xi Jinping sent Liu a "get well" message, state media reported on Tuesday.

The ruling Communist Party's leadership had been "very concerned about Liu Xiang's injury, and hopes he will receive swift treatment and soon heal", said the message from Xi issued by Xinhua news agency.

"Everyone will understand why Liu Xiang had to abandon competition due to injury, and we hope he will cast aside mental burdens and settle his mind on overcoming injury," said Xi, favoured to succeed Hu Jintao as president in five years.

Liu's departure has dominated talk and commentary in China, overshadowing the nation's leading gold medal haul. His mother, Ji Fenhua, said the 25-year-old felt the pressure of adulation.

The People's Daily website (www.people.com.cn) criticised Internet speculation that Liu folded under pressure on home soil.

"Perhaps a nation of 1.3 billion should not place the burdens of its aspirations on a boy's shoulders," a commentary said.