By Ben Blanchard

BEIJING (Reuters) - A military court in China on Monday jailed for life a former top military officer for corruption, stripping him of his title of general and seizing his assets, the latest prosecution in President Xi Jinping's drive against graft in the armed forces.

Guo Boxiong, 74, was a vice chairman of the powerful Central Military Commission until he stepped down in 2012. Last year, the government said it would prosecute him for graft.

The official Xinhua news agency said in a report also carried on the Defence Ministry website all of Guo's "illicit money and materials" had been confiscated and turned over to the state.

Guo's case was held behind closed doors as it involved military secrets, Xinhua said without elaborating.

Guo abused his position to help others with promotions and took "massive" bribes, either on his own or in connivance with others, Xinhua said.

Guo admitted to his crimes, expressed regret and accepted the judgment. He would not appeal, Xinhua said.

A commentary carried on the Defence Ministry's website said the fight against graft was a "life and death" struggle for the military.

"Corruption is the greatest threat our party faces, and is the top killer of the military's fighting ability," it said.

Guo's son, a major general, Guo Zhenggang, was put under investigation too, last year.

It has not been possible to reach either Guo for comment and it is not clear who their lawyers are.

His case follows that of Xu Caihou, who was a Central Military Commission vice chairman at the same time as Guo, and died of cancer last year.

Before their retirement, the men had been two of China's top military officers who served together under Xi's predecessor, Hu Jintao. Xi was also a vice chairman with Guo and Xu from 2010-2012, before he became head of the party and military commission chief.

Sources have told Reuters that Guo is also suffering from cancer and the military had faced a quandary over whether to put him on trial, in case he died before reaching court, like former comrade Xu.

Serving and retired officers have said graft in the armed forces is so pervasive it could undermine China's ability to wage war. Xi has made ending military corruption a top goal.

The anti-graft drive comes as Xi steps up efforts to modernize forces that are projecting power across the disputed waters of the East and South China Seas, though China has not fought a war in decades.

(Editing by Clarence Fernandez, Robert Birsel)