China has accused a US spy plane of entering a no-fly zone during a live fire military exercise in the north of the country.
The Chinese ministry of national defence said the US Air Force U-2 aircraft had "seriously interfered" with the exercise and "severely incurred the risk of misjudgement and even of bringing about an unintended air sea incident".
The ministry spokesperson described it as a "naked act of provocation", adding China has lodged a stern protest and demanded the US to stop such actions.
The statement did not give details on the time and place of the drill, but the information matches exercises the maritime safety administration said started on Monday and would run until 30 September over the Bohai Gulf, east of Beijing.
China is also holding naval drills in the South China Sea, which it claims virtually in its entirety, despite five other governments also putting forward claims.
Beijing objects to all US military activity in and over the South China Sea, particularly "freedom of navigation operations" which sees US Navy ships sail close to Chinese-held islands.
Relations between the US and China are at their lowest in decades due to disputes over issues like the South China Sea, as well as trade, technology and Taiwan.
Another naval exercise is planned from Thursday 27 August to 30 August in the East China Sea, despite warnings issued over Typhoon Bavi.
Earlier this month, the Chinese defence ministry said exercises held in the Tawian Strait were a "necessary move responding to the current security situation" in the waters and were "meant to safeguard national sovereignty".
China claims Taiwan is part of its territory and threatens to use military force to bring under its control the island that is a self-governing democracy and a close US ally.
In recent years, the US and Taiwan have increased military and governmental contacts.
This month, Alex Azar, US health and human services secretary, became the highest-ranking US official to visit Taiwan, prompting a Chinese protest.
Cover image: Library photo of a US Air Force U-2 (Picture: US Department of Defense).