BEIJING (AP) -- A Chinese politician once considered a potential future leader has been removed as the head of the central mega-city of Chongqing amid reports he is facing a graft investigation.
The move, just ahead of a crucial Communist Party congress later this year, is a sign of the intensifying political tussling behind the scenes to shape the lineup of top party personnel before the congress convenes, analysts say.
Citing unidentified sources, the South China Morning Post reported Monday that Sun Zhengcai is being investigated by the party's anti-graft arm. The Central Commission of Discipline Inspection has not formally announced any probe of Sun.
But an official statement is expected to come soon, said Willy Lam, a long-time observer of China's elite politics at the Chinese University of Hong Kong.
"I am sure Sun's political career is finished," Lam said.
Sun's removal has added fuel to speculation churning in recent months that Chinese President Xi Jinping could try to seek a third term rather than appoint his successor this year, Lam said.
Sun sits on the party's 25-member Politburo and had been seen as a candidate for promotion this year to the body's Standing Committee, the apex of political power in China.
Newly promoted Standing Committee members would have a shot at succeeding Xi. The party often signals during the congress who is being groomed to be the next top leader.
"It looks like Xi is building himself to be the Mao Zedong of the 21st century," Lam said, referring to the party's founding revolutionary, who ruled China for decades until his death in 1976.
Lam said Sun might be faulted for not cleaning up the mess following the downfall of his predecessor, Bo Xilai, in 2012. Bo was a political rival of Xi's before Xi was elected to the top position five years ago.
The Chongqing government said on its website Saturday that Sun would be replaced as head of the city's Communist Party committee by Chen Min-er, another rising star reputed to enjoy a close relationship with Xi.