The country's biggest airshow, in the southern coastal city of Zhuhai, comes as Beijing pushes to meet a 2035 deadline to retool its military for modern warfare.

China still lags the United States in terms of tech and investment in its war machine, but experts say it is narrowing the gap.

A US intelligence report this year flagged China's growing influence as one of America's biggest threats.

On Tuesday, a prototype of a new surveillance drone able to carry out attacks -- the CH-6 -- was among domestic tech unveiled in Zhuhai.

With a wingspan of 20.5 metres (67 feet) and 15.8 metres long, the drone can carry missiles and is designed for surveillance and strike operations, according to open source intelligence agency Janes.

Other debutants include the WZ-7 high-altitude drone for border reconnaissance and maritime patrol, as well as the J-16D fighter jet which can jam electronic equipment.

Both have already entered service with the air force, state media reported.

"They will play a major role in both the Taiwan Strait and the South China Sea," military commentator Song Zhongping told AFP.

China claims virtually all of the South China Sea -- disputed with several other nations -- while Beijing says the self-ruled island of Taiwan is an inviolable part of its territory.

China is also "clearly positioning itself to be an alternative supplier" of advanced drones, with relative affordability, said Janes analyst Kelvin Wong.

The United States and European countries have been hesitant to supply such equipment outside a select group of partners, he added.

Already, Chinese drones have seen combat action in the Middle East, with sales to other regions as well.

Similarly, the J-16D shows "overall improvement" in the combat capabilities of the People's Liberation Army, said James Char, a Chinese military expert at Singapore's Nanyang Technological University.

"This is indeed a significant development since it gives the Chinese military an advantage in terms of conducting aerial electronic warfare over targets that possess significant air defence capabilities," he said.

Under president Donald Trump, Washington authorised around $18 billion worth of arms sales to Taiwan, including advanced missile platforms -- sales that have angered Beijing.

The J-16D has wingtip pods to disrupt enemy electronic equipment and has drawn comparisons with the US Navy's EA-18G Growler.

The airshow, which is usually held every two years, was postponed from last year due to the Covid-19 pandemic and is being held before a largely domestic audience due to quarantine and travel restrictions.