China deems the U.S. U-2 plane's entrance into a no-fly zone as a purely provocative act, said a Ministry of National Defense spokesperson Wu Qian on Tuesday.

The plane was reported to have entered into a no-fly zone enforced by the Northern Theater of the People's Liberation Army (PLA). 

According to Wu, the move severely encroached on China's sovereignty, heavily interrupted China's ordinary military operations and could easily cause misjudgment and even result in accidents.

China urged the U.S. to correct its mistake and refrain from further patrols, said Wu, stating that the Chinese army will firmly do its duty to defend the country's sovereignty and safety with concrete actions.

(Cover: A U.S. Air Force U-2s spy plane lands at the Osan Air Base in Pyeongtaek, the ROK, December 4, 2017. /Reuters)