Chinese military would closely monitor US flights and adopt appropriate measures to ensure the country's security, Ministry of Defence Col Yang Yujun told a news briefing.
He said it has become a routine for the US to show-up off Chinese coast. "In particular when PLA conducts weapon tests in maritime area US showed up without an invite."
"This behaviour could easily cause misperception and cause air and sea accidents," Yang said.
He said American fighter jets have conducted frequent reconnaissance against China for a long time, which has "gravely undermined China's security interests as well as China-US strategic mutual trust and bilateral ties."
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If the US does not want to affect bilateral ties, it must reduce and ultimately stop such reconnaissance, state-run CCTV reported as Yang having said.
Yang's comments came as China and the US are at odds over an incident last week in the skies 220 kilometres off Hainan island -- the smallest and southernmost province of China.
The encounter has raised comparisons to an incident in April 2001, when a Chinese fighter jet collided with a US Navy EP-3 spy plane around 110 kilometres off Hainan.
The Pentagon had claimed that the August 19 interception was "dangerous."
Yang, however, said it's not "a Chinese intercept" but "US close-in reconnaissance."
"What I need to stress is that the US has kept talking about the technical issues like the distance between the two aircraft, but ignored a policy issue of highly-frequent close-in reconnaissance activities against China," he said.
"But indeed the Chinese pilot's operation is professional and has taken safety into consideration.