Dong's promotion comes at a sensitive time as Beijing ups military pressure on the self-ruled island of Taiwan ahead of presidential elections next month.

It also comes as China and the United States seek to re-establish military-to-military lines of communication -- crucial if the two powers are to stop competition from turning into conflict.

Dong was appointed at a meeting of the standing committee of China's National People's Congress, state news agency Xinhua said.

Beijing has not given an official reason for Li's removal after his seven months in the role, which followed a lengthy disappearance from public view.

His ousting was one in a series of high-level demotions in the country's military establishment.

Three executives at leading Chinese missile defence firms were removed from Beijing's top political advisory committee this week, according to state media.

Fighting alleged corruption has long been a central theme of Chinese President Xi Jinping's rule, which has been punctuated by high-level removals and disappearances of officials.

Recent months have also seen an overhaul in the leadership of China's secretive Rocket Force, the army unit that oversees Beijing's nuclear arsenal, following media reports of a corruption probe involving its former chief.

- Surprise promotion -

Dong, born in 1961, was made commander of the navy in August 2021.

He was replaced by Hu Zhongming earlier this month.

Dong previously served as deputy commander of the Chinese military's Southern Theater Command, which includes as its area of operation the South China Sea, where Beijing has territorial disputes with neighbouring countries.

His promotion comes as a surprise, however.

Many analysts had expected Liu Zhenli, a 59-year-old general and head of China's joint staff department, to become the new defence minister.

He notably spoke last week with his American counterpart during the first high-level call in more than a year between military personnel from the two leading world powers.

That followed an agreement by President Joe Biden and Xi at a summit last month to restore military communications between their two countries, which China severed after then US House speaker Nancy Pelosi visited Taiwan in 2022.

Biden at the time said the move was "critically important" to avoid possible conflicts.

But that summit also saw Xi warn the US president against supplying further arms to Taiwan, insisting China's reunification with the island was "unstoppable".