China’s leader-in-waiting Xi Jinping has been mysteriously missing from public view for 10 days now, but the Chinese government is refusing to explain why, even as rumours swirl.

The 59-year-old Xi is due to assume the presidency in March, 2013. Ahead of that, he is to take over as head of the ruling Communist Party later this year. And yet, no date for the handover ceremony has been announced.

Xi's last public appearance was at the opening of the Communist Party training academy's fall session, on Sept. 1. Since then, he has skipped several meetings with visiting foreign leaders, including U.S. Secretary of State Hillary Clinton and the prime ministers of Singapore and Denmark.

On Sunday, he also missed an emergency meeting of the Central Military Commission, of which he is a vice chairman, called to discuss earthquake recovery work.

China’s Communist government has a long history of maintaining official secrecy when it comes to the health of senior leaders and appears to be sticking to that policy, even amid ongoing speculation both within China and abroad.

Foreign Ministry spokesman Hong Lei told a news conference Tuesday he had "no information in this regard" when asked about Xi's condition and whereabouts.

Asked whether Xi was still alive, Hong replied: "I hope you can ask more serious questions."

Nevertheless, Xi's absence -- and the silence from the government -- has sent the Chinese rumour mill churning.

Two sources close to the Beijing leadership tell Reuters that the portly Xi is nursing an injury, after he hurt his back while out for a swim. But both refused to give any details on the injury or say when it occurred.

Other rumours suggest Xi has suffered a stroke. Another story says a soccer injury. Yet another has blamed golf.

There are even conspiracy theories that suggest Xi was injured in a car crash in a staged assassination attempt.

The uncertainty about Xi’s status is leading to uncertainty at a time that was supposed to be marked by a smooth handover of power to younger officials. It also comes as China's once unstoppable economy grows sluggish and the risk of social unrest ticks upward.

As the tension rises, rumours are being dealt with as they often are in China: with the government blocking Internet searches seeking info on Xi’s status, including blocks on terms such as “back injury” or “car accident.”

With a report from CTV’s Beijing Bureau Chief Janis Mackey Frayer