Police detained a mentally ill male passenger who held a crew member hostage, using a pen as a weapon, on an Air China flight from Changsha to Beijing, local police said on Sunday.

The suspect, identified only as Xu, 41, from Anhua, Central China's Hunan province, has a history of mental disease and was detained at about 1 pm Sunday, the Department of Public Security of Henan province said. The flight, CA1350, was diverted to Zhengzhou in Central China's Henan province.

After the preliminary investigation, it was learned that during the flight Xu suddenly appeared mentally abnormal and held a crew member with the pen, which led to the diversion, police said.

No one was injured in the incident, which is under further investigation, police said.

The diversion to Zhengzhou Xinzheng International Airport was made for "public safety reasons", China's aviation authority said Sunday.

The crew, in its decision to divert to Zhengzhou, followed official procedures, the Civil Aviation Administration of China said.

The flight landed in Zhengzhou at 9:58 am and all passengers exited the plane and entered the terminal buildings safely at 10:50 am, Henan Airport Group said.

The plane departed Changsha, Central China's Hunan province, at 8:40 am and was expected to arrive in Beijing at about 11 am.