"US warplanes are constantly conducting reconnaissance flights close to Chinese coastal areas which is a great threat to China's air and marine security…. We demand that the United States stop close reconnaissance flights and prevent repeated incidents," Hong told journalists at a briefing.
Earlier, the Pentagon said two Chinese fighters had intercepted a US reconnaissance plane that was on a routine patrol in international airspace over the South China Sea on May 17.
The South China Sea has recently seen increased tensions between Washington and Beijing as both try to reaffirm their dominance in the region. US air and naval patrols persistently challenge China's claims over territories disputed with Brunei, Malaysia, Vietnam, the Philippines and Taiwan.
