BEIJING (AFP) - The Chinese Communist Party's dramatic expulsion of a former top general - the most senior figure to fall in President Xi Jinping's anti-corruption campaign - is an assertion of political control over the powerful and wealthy military, analysts say.

Xu Caihou, former vice-chairman of China's Central Military Commission and until two years ago a member of the ruling party's elite 25-strong Politburo, was stripped of his party membership on Monday and his case was handed over to prosecutors.

The 71-year-old is the highest-ranking Chinese military officer to face trial in decades.

The authorities' move to pursue charges against him - despite reports that he is dying of bladder cancer - is intended to send the People's Liberation Army (PLA) a clear message, analysts said.

The PLA's influence in domestic affairs has waned since the days of Communist China's founding father Mao Zedong, but it remains a political force to be reckoned with and has at the same time built up a vast network of business interests.

Mr Xi presided over the meeting that decided to expel Xu, the official news agency Xinhua stressed.

The expulsion "definitively puts to rest any notion that Mr Xi is not fully in command of the CCP and its military", according to Christopher Johnson, the Freeman Chair in China Studies at CSIS in Washington.

The announcement made explicit reference to Xu enabling the buying of military office, he pointed out, suggesting "Xi and his civilian peers are keen to send a message concerning the party's control of the military".

"The accusation goes right to the heart of the PLA's loyalty to the CCP and its role as the ultimate guarantor of party rule," he wrote in an analysis.

Authorities have not yet released full details of the accusations against Xu, but some reports state that according to military officers briefed on the case, he and his family members received tens of millions of yuan in bribes.

China's military spending has seen double-digit annual increases in recent years, with the official 2013 defence budget reaching US$119.5 billion (S$ 150 billion), according to Beijing - far eclipsing the expenditure of neighbours including Russia (US$69.5 billion), Japan (US$56.9 billion) and India (US$39.2 billion), although still well below the US's US$495.5 billion.

Experts say the spending spike has brought with it more opportunities for corruption within the ranks, a trend compounded by the difficult task of disentangling the PLA from the commercial interests it developed over decades.

The web of connections is so extensive that academics have coined a term to describe it: "PLA Inc".

"When Deng Xiaoping took over (as paramount leader in 1978), there were the Four Modernisations," said Brad Glosserman, executive director of the Pacific Forum CSIS and an Asian security expert "One of the things that Deng commanded was, 'We either get the PLA out of business, or you get out of the PLA'," he said of the order to businessman officers.

"This intermingling of interests has been slow to reverse and undo; that's been a real source of the problem," he added.

"I think a lot of people believe that there's some pretty extensive corruption. There's a sense that this mingling of interests is undermining the ability of the PLA." Since taking office, Mr Xi has repeatedly urged the armed forces - whose combat experience is limited, despite Beijing's sometimes assertive approach in maritime territorial disputes with its neighbours - to strengthen their capacity to "win battles".

The move to take down Xu also suggests a calculation by Xi that it is impossible to fully consolidate power without asserting control over the military, analysts say.

As a son of a Chinese revolutionary leader, Mr Xi already had stronger credentials with the PLA than did his predecessor Hu Jintao. He has strengthened that relationship over the past year with a high number of visits to military bases.

"Xi Jinping's relationship with the military is good because of his 'princeling' background and his earlier career as secretary to the secretary-general of the military commission" Geng Biao, said Joseph Cheng, professor of political science at the City University of Hong Kong.

For his part Xu was born in the north-eastern province of Liaoning in 1943 and graduated from the Harbin Institute of Military Engineering before rising through the ranks of the PLA, including a stint as the director-general of its General Political Department.

But the connections he built up could not save him once the decision to purge him was taken.

A front-page editorial Tuesday by the PLA Daily backed his expulsion and called for all military officers to "firmly support the correct decision of the CPC Central Committee... and ensure all their actions follow the instruction of the CPC Central Committee, the CMC and its Chairman Xi Jinping."