According to the illustration shown on Twitter, the P8-A flew through the Bashi Channel towards the Taiwan-controlled Pratas Islands – a group of three atolls in the northern reaches of the South China Sea that are known by Beijing as the Dongsha Islands – before flying close to the southeast coast of the Chinese mainland.

Pratas Island, the largest of the three atolls, lies midway between China’s military base on its island province of Hainan and the Pacific Ocean, and therefore has great strategic significance.

Japan’s Kyodo news agency reported earlier that the PLA was planning to stage a large-scale landing exercise off Hainan in August in preparation for the possible future seizure of Pratas Island.

Aware of Beijing’s plans, the US had deployed electronic-warfare aircraft to carry out several intelligence-gathering missions in the same area, the report said.

Despite the SCSPI tweet, Taiwan on Thursday declined to confirm any US Air Force activity in the region.

However, its defence ministry said PLA Sukhoi-30 and Jian-10 fighter jets, and Yun-8 transport planes had entered the southwestern section of Taiwan’s air defence identification zone 11 times this month – including eight times in the past two weeks – prompting the island’s air force to scramble jets to warn them off.

Military analysts said the presence of the P8-A in the region suggested the American missions might have something to do with the movements of the PLA’s nuclear-powered submarines close to the Philippine Sea.

“If China deployed its submarines in the Bashi and Balintang channels between Taiwan and the Philippines, it would serve as a deterrent to US naval operations between the Philippine Sea and South China Sea,” said Alexander Huang Chieh-cheng, a professor of international relations at Tamkang University in Taipei.

“Also, it might imply China’s intention to achieve greater ‘sea control’ between its coast and the first island chain,” he said, referring to the waters of the Bohai, Yellow, East China and South China seas that lie between mainland China and the western Pacific.

Huang said that although the American and Chinese militaries had ramped up their activities in the waters and skies around Taiwan in recent months, it did not necessarily mean the situation had arisen out of a lack of trust.

“Rather, it’s down to an absence of efficient communication and meaningful military-to-military dialogue,” he said.

Couple that with the hawkish comments coming out of Beijing and Washington and it was inevitable there would be more misunderstanding and miscalculation by the military, he said.

In an article published in Singaporean newspaper The Straits Times on Monday, Beijing’s ambassador to the city state Hong Xiaoyong accused US Secretary of Defence Mark Esper of “fuelling tensions by labelling China a threat and calling for joint deterrence”.

China ignores US fears with strategy to use civilian tech for military

US Pacific Air Forces Commander General Charles Brown echoed that sentiment on Wednesday, saying he was concerned by the increase in China’s military activity in the region.

He said that when he assumed regional command in 2018 – he is set to leave the position next month – the PLA hardly ever flew its H-6 bombers over water.

“Now it’s an everyday occurrence,” he said.

“I’m concerned by increasingly opportunistic activity by [China] to coerce its neighbours and press its unlawful maritime claims while the region and the world is focused on addressing the [Covid-19] pandemic.”