As China flexed its most advanced stealth fighter jets fitted with home-grown engines at the nation's biggest air show, a Chinese commander responded to an American challenge with an invitation to the US military to meet the PLA "in the sky" .

• Drones and jets: China shows off new air power

The comments on Wednesday by deputy air force commander Wang Wei of the People's Liberation Army came after US Air Force Secretary Frank Kendall said in August that China's military modernisation programs had been faster than expected, and there was a need for the US to stay ahead with more leading technologies that "scare China".

Responding to the comment during the Zhuhai Airshow on Wednesday, Wang said "recently a counterpart of mine who is from a major country claims that he wants to scare China".

"The Chinese navy is capable and confident to ensure national security and defend integrity, as well as make a contribution to world peace," he said.

"I can only say, if they are not scared (by China's capabilities), let us meet in the sky."

The Zhuhai Airshow, officially known as the China International Aviation and Aerospace Exhibition, is held every second year but was postponed in 2020 for almost a year because of the coronavirus pandemic.

Chinese military and aerospace firms have had a stronger presence at the show, with strict quarantine rules limiting attendance from overseas.

A key theme this year is China's effort to replace foreign technologies with domestic creations, key to the nation's self-sufficiency drive amid an intensifying strategic rivalry with the US.

A J-20 fighter jet powered by a domestic engine made its debut at the air show this year, PLA Air Force spokesman Shen Jinke confirmed on Tuesday.

China has been working to address an enduring bottleneck creating a lack of quality engines. The capabilities of the J-20, like all Chinese aircraft, have been limited by a lack of durable and high-performance jet engines.

The PLA has not officially announced the engine model used. The South China Morning Post has previously reported it to be the WS-10C, a modified version of the WS-10 engine replacing Russian AL-31F engines.

But a military insider said the WS-10C was a stopgap choice for the J-20, and that the fighter jet would better fulfil its potential with the more powerful WS-15.

J-20 deputy chief designer Wang Haitao said on Wednesday that China expected to speed up the upgrade for the J-20 and had been working to scale up production.

The Y-20 strategic transport plane is also in the process of having its foreign engine replaced. Its chief designer Tang Changhong said the PLA had also paired domestic engines with the Y-20 and conducted test flights.

Tang said the new Chinese engines consumed less fuel, flew for longer and could carry heavier cargo.

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