An Air China flight bound for New York returned to Beijing Capital International Airport on Wednesday after an unspecified threat was received, Xinhua news agency reported, citing security officials.

Flight 981 was diverted back to its point of origin over concerns for passengers' safety, Air China announced through its account at Chinese socialmedia site Sina Weibo. The airline didn't specify the nature of the threat or offer further details about the incident.

The flight was a Boeing 747 jumbo jet that seats up to 344 passengers in the Air China's configuration, mainly for travel between China and the United States. It was scheduled to take off from the Beijing airport on Wednesday at 1 pm (1 am Eastern) and land nearly 13 hours later at New York's John. F Kennedy International Airport. At 8:26 pm, more than halfway through the flight, the plane headed back to Beijing, according to Air China's website.

After authorities found nothing suspicious aboard the plane and passengers and their luggage were re-screened at security checkpoints, the 747 took off again, at 12:31 am Thursday, according to a brief message on the airline website.

One passenger, identified as Wang Qiang, an official in China's Ministry of Science and Technology, said he thought something was wrong when the on-board electronic flight map showed the plane heading in the direction of Beijing. However, flight attendants told him it was only a map display error.

Authorities haven't released additional information, saying only that an investigation is underway.

Yang Rui, deputy general manager of Air China North America, told China Daily: "Flight safety is very important. We won't take any risk."

Wang Jun in Los Angeles contributed to the story.

Contact the writer at yuwei12@chinadailyusa.com.