Where is China's defense minister? Mystery over Li Shangfu's fate deepens

Mystery deepened Friday over the fate of China's defense minister, who has not been seen in more than two weeks — an unexplained absence that comes two months after the disappearance and then replacement of the country's foreign minister.

As is the norm in China’s opaque system of government, little is known about why Li Shangfu, 65, has not been seen in public since Aug. 29. But a rush of reports in the Western media, as well as public comments by a top U.S. diplomat, have fueled growing speculation.

His future is of great interest in the West, which will be eager to see if Li might be the latest target of a crackdown by the increasingly powerful President Xi Jinping. The removal of Qin Gang as foreign minister and a recent shake-up at the top of the country's nuclear forces come as Beijing also grapples with economic troubles and spiraling tensions with the United States.

“Clearly there’s some turbulence at the top of the party,” said Alexander Neill, a Singapore-based strategic adviser on Asia-Pacific geopolitics, who noted it was too early to tell exactly what, if anything, has happened to Li.

But "stepping back a bit, clearly there’s a purge within the foreign affairs and defense community," he told NBC News.