China's Liaoning aircraft carrier battle group has conducted its first exercises with live ammunition, the country's navy said, in a show of strength as tensions with the US and Taiwan escalate.

China's first and only aircraft carrier led large-scale exercises in the Bohai Sea, the People's Liberation Army Navy said late Thursday in a statement on their website.

The drills involved dozens of ships and aircraft in the carrier group and saw more than 10 air-to-air, anti-ship, and air defence missiles being tested, it said.

The group also performed reconnaissance exercises, tests of early-warning systems, aerial interception, and missile defence.

The goal of the exercises was to "test the performance of weapons and the training level of the team", the statement said.

China's national broadcaster CCTV showed footage of J-15 fighter jets taking off from the carrier and firing missiles.

The drills come as a heated war of words intensifies between Beijing and US President-elect Donald Trump, who broke convention by speaking directly to Taiwanese president Tsai Ing-wen and even suggested Washington could jettison Washington's decades-old "One China policy".

The "One China policy" is a diplomatic compromise allowing the US to do business with both China and Taiwan while only recognising Beijing.

Since Trump's and Tsai's phone call, China has sent military aircraft close to Japanese territory near the Miyako Strait and reportedly sent a bomber to circumnavigate disputed territory in the resource-rich South China Sea, flights its air force has described as "routine".

The US Pacific commander said Wednesday that the US will keep challenging China's "assertive, aggressive behaviour in the South China Sea", despite Beijing's rapid development of artificial islands capable of hosting military planes.

Satellite images published this week by a US think tank showed structures on Chinese-built artificial islands that appeared to be large anti-aircraft guns and close-in weapons systems (CIWS) designed to take out incoming missiles and enemy aircraft, the think tank said.

China's defence ministry said on a verified social media account that the construction was mostly for civilian use, and that necessary military installations were for self-defence.

"If someone were flexing his muscles outside your door, wouldn't you get a slingshot ready?", it wrote.

Beijing is seeking to build a "blue water" navy capable of operating in distant seas and has embarked on an extensive project to modernise its two million-strong military, the world's largest.

The Liaoning is a secondhand Soviet ship built more than 25 years ago. It was commissioned in 2012 after extensive refits.

In December 2015, China's defence ministry announced the country was building a second aircraft carrier based entirely on domestic designs.