An American spy plane came within 200 metres of a scrambled Chinese fighter jet near Hong Kong, according to US officials.
The P-3 Orion surveillance plane was in international airspace when it attracted the attention of two Chinese aircraft.
Flying in front of the US plane, one of the jets "unsafely" intercepted the spy craft and restricted its ability to manoeuvre.
The incident, on Wednesday, took place 150 miles southeast of Hong Kong, the officials told Reuters news agency.
ABC News quoted officials describing the encounter as "unsafe and unprofessional", with the US set to take up the issue with China through diplomatic and military channels.
It comes exactly a week after Chinese jets came within 45 metres of an American WC-135 plane, which was taking samples in order to detect radiation in international airspace over the East China Sea.
One of the jets was reported to have flown upside down directly above the aircraft in a move similar to the one performed in the Hollywood movie Top Gun.
The news of the P-3 Orion intercept emerged a day after a US warship sailed within 12 miles of an artificial island built by China in the South China Sea, drawing an angry response from Beijing .
China's island-building programme is subject to numerous international disputes over the region's territorial waters.
US officials said the warship had moved through the area to show it did not belong to Beijing.
The tensions in air and sea come at a time when US President Donald Trump is hoping to woo China into taking a tougher line against North Korea.
Last month, Chinese president Xi Jinping was entertained by Mr Trump at his Mar-a-Lago estate in Florida.
The US president informed his fellow leader he had launched missile strikes on Syria as the pair ate "the most beautiful piece of chocolate cake that you have ever seen", Mr Trump revealed.