BEIJING (REUTERS, AFP)- An Air China flight bound for Beijing made an unscheduled landing in the central Chinese city of Zhengzhou on Sunday (April 15) after a passenger threatened a flight attendant with a fountain pen, the country's civil aviation authority said.

In a brief statement on its website, the Civil Aviation Administration of China said a male passenger on Air China Flight 1350, who it did not identify, attempted to use the pen to hold the flight attendant "under duress".

Chinese police said preliminary investigations found the 41-year-old passenger, identified only by his last name Xu, had a "history of mental illness".

He has been arrested and the female crew member was unharmed.

The other passengers and crew were unharmed, the statement said, without providing any further details.

The flight took off from Changsha, the capital of southern Hunan province, at 8.40 am and was scheduled to arrive at Beijing Capital International Airport at around 11 a.m., according to local media reports and flight tracking websites.

But it made the unscheduled landing at Zhengzhou Xinzheng International Airport, in central Henan province, at 9.58 am, according to an earlier post on Air China's official Weibo microblog.

A photo posted by China News Service showed a handful of firefighters standing in front of a row of fire trucks outside Zhengzhou airport.

"I think someone uttered a cry, which woke us. Everyone was sleeping... it was a woman's cry. Nobody knew what was going on," one passenger recounted, according to a video produced by Tencent News and Beijing News.

The crew kept passengers calm and in their seats, he said. Another passenger said flight attendants told passengers they had to land at a different airport but she had not heard of anything amiss.

"We exited from the back so we didn't see whatever happened in the front, and didn't hear anything either," she said.