China's state-run media warned Washington on Monday that Beijing could treat its surveillance flights as an "act of hostility", after accusations a Chinese fighter jet flew dangerously close to a US military aircraft.

US Rear Admiral John Kirby said Friday the armed Chinese warplane came close to the American P-8 Poseidon surveillance aircraft on three occasions, at times less than 30 feet (nine metres) away, in what he called a "very dangerous" intercept.

China's defence ministry spokesman Yang Yujun called the allegations "totally groundless" in a statement cited by the official news agency Xinhua.

The incident took place 220 kilometres (135 miles) off China's Hainan island, over an area the US insists is international waters but Beijing regards as part of its territory.

The incident has echoes of a major incident in April 2001, when a Chinese fighter jet collided with a US Navy EP-3 spy plane around 110 kilometres off Hainan.

The Global Times -- which is owned by the Communist Party's mouthpiece, the People's Daily, and often takes a nationalist tone -- lashed out in an editorial at US surveillance "in the coastal waters and airspace of China".

"Such reconnaissance is posing a threat to China's core security interests, which could be treated as an act of hostility," it said.

"It would be a life and death fight between China and the US if the collisions in the South China Sea became confrontations concerning both sides' core interests," it warned.

The episode comes as Beijing builds up its military might and naval reach, while Washington is engaged in a foreign policy "pivot" to Asia.

The official China Daily newspaper accused the US of undermining mutual trust, saying that Washington's concerns over China's rise were a "psychological need to create an enemy to make up for its sense of loss after the end of the Cold War".

US naval and airborne reconnaissance missions "do nothing to convince the Chinese authorities and the Chinese people that the US is sincere in claiming it wants to build mutual trust with China," the paper said in an editorial.

Washington and Beijing have long disagreed over aviation and maritime rights in the strategic South China Sea, the site of key shipping routes, which Beijing claims almost in its entirety.

In the 2001 collision, a Chinese pilot was killed and the American aircraft was forced to make an emergency landing on Hainan.

Chinese authorities initially detained its 24-member crew for more than a week until both governments worked out a face-saving deal for their release.