BEIJING (Reuters) - China has appointed new commanders of its army and air force in a reshuffle ahead of next month’s Communist Party congress, as President Xi Jinping brings new blood into the military’s top ranks amid an ambitious modernization program.

China's People's Liberation Army (PLA) Gen. Li Zuocheng, center, speaks during a meeting with U.S. Army Chief of Staff Gen. Mark Milley, not shown, at the Bayi Building in Beijing, Tuesday, Aug. 16, 2016. REUTERS/Mark Schiefelbein/Pool

China’s armed forces, the world’s largest, are ramping up their capabilities with new equipment like aircraft carriers and stealth fighters as the country pursues a more assertive stance in the disputed East and South China Seas and seeks to project power far from home shores.

The new army chief, Han Weiguo, is not a high-profile figure but has risen rapidly, with three promotions since 2015.

He was also commanding officer in charge of a military parade in Inner Mongolia in July overseen by Xi to mark 90 years since the founding of the People’s Liberation Army.

Han had previously served as head of the central theater command, a military district that includes Beijing and a large swathe of central China.

His new position was announced by state media on Friday. The army has been less of a focus of the military modernization, with more resources poured into the air force and navy that have increasingly been carrying out drills in distant regions.

The new air force chief, Ding Laihang, announced by the Defence Ministry on the same day, is also a relatively low-profile figure, who ran air force operations for China’s northern theater command before his promotion.

New navy chief Shen Jinlong took up his position in January. Sources with ties to the leadership say he is close to Xi.

All three men could be promoted to the Central Military Commission headed by Xi, which is in overall charge of the People’s Liberation Army, when the party holds its once-in-five-years congress in Bejing next month.

Another promotion was announced in August, with previous army commander Li Zuocheng being made the new chief of the Joint Staff Department of the People’s Liberation Army.

Li has had a much higher profile, as one of the few senior military officers with combat experience, having fought Vietnam in a brief border war in 1979.

Last year he was glowingly profiled in the official Beijing Daily, which described his time fighting the Vietnamese, accompanied by black-and-white pictures of the then 26-year-old in a trench and pointing to a map.

It was not clear what had happened to Fang Fenghui, the chief of the Joint Staff Department before Li.

At a news briefing on Thursday, Defence Ministry spokesman Ren Guoqiang declined to comment on Fang, who turns 67 next year, usually around the age at which Chinese officials retire.