An Air China flight was forced to make a landing in central China for an unspecified "public security" reason with all passengers making it safely off the plane.
China Central Television said on its official account on the microblog Weibo.com that Air China Flight 1350 took off at 8.40am on Sunday local time from the city of Changsha in Hunan province heading for Beijing.
But it said it landed in Zhengzhou city at 10am due to an "illegal interference".
CCTV's post included an image of what appears to be paramilitary police in combat uniforms and helmets assembled outside a Zhengzhou airport hotel.
The Zhengzhou airport said it immediately activated emergency measures and that it was operating normally.
China's civil aviation authority later said a male passenger had tried to hold a flight attendant hostage using a fountain pen as a weapon.
The Beijing News said that a passenger described being awoken by a scream coming from the front of the plane and that "nobody knew what was going on".
The Xiaoxiang Morning Herald quoted a passenger as saying the disturbance occurred in the first or business class cabins but that the curtains separating those sections from economy class were pulled tightly shut.