He Weidong, the Central Military Commission (CMC) vice chairman, was among nine individuals to be expelled from the army for having "seriously violated" discipline, according to an online statement by defence ministry spokesman Zhang Xiaogang.

While rumours swirled as He had not been seen in public since March, a formal investigation had not been previously announced.

Also named was Miao Hua, the former head of the military's political work department who was formally removed from his post, according to state media reports in June.

Eight of the individuals were expelled from China's ruling Communist Party, after previously serving on its elite Central Committee, Zhang said.

"The severe punishment of He Weidong, Miao Hua... and others once again demonstrates the Party Central Committee and the CMC's unwavering resolve to persevere in the fight against corruption," said Zhang.

Xi has made rooting out alleged graft from all levels of government a top priority since coming to power just over a decade ago.

He has called graft "the biggest threat" to the Communist Party and said "the fight against corruption remains grave and complex".

Proponents say the policy promotes clean governance, but others say it also serves as a tool for Xi to purge political rivals.

The latest announcement comes as the Communist Party prepares to convene a key meeting Monday known as the "fourth plenum" focused on economic planning for the five-year period ending in 2030.