Beijing (CNN) -- An unspecified threat forced a New York-bound Air China flight to return to Beijing on Wednesday seven hours after takeoff, the airline said.
"Due to threatening information received about flight CA 981, to ensure the safety of passengers, this flight has returned to Beijing Capital International Airport," the Chinese flag carrier said in a terse statement posted online.
The flight took off at 1:30 p.m. (1:30 a.m. ET) Wednesday and was scheduled to land at John. F. Kennedy International Airport in New York at 2:20 p.m. the same day. Instead, it turned around midair and returned to Beijing at 8:26 p.m. Wednesday, according to the airline's website.
Police were called in to investigate but found nothing suspicious, the airport authority said in statements posted online. State media also quoted police as saying the initial warning of the threat came from U.S. authorities.
The flight took off again at 12:31 a.m. Thursday and is expected to arrive in New York at 12:45 a.m. the same day, according to the airline's website.
Beijing-based Air China did not reveal the nature of the threat or the number of passengers and crew members on board its Boeing 747 jumbo jet. The aircraft seats up to 344 passengers in the carrier's configuration, and it is peak travel season between China and the United States.
Messages and photos posted on Chinese social-media sites showed passengers and their luggage being rescreened at the airport upon landing.
One passenger, whose online handle is Kejiwaijiao, said he noticed something was wrong when the flight map on board indicated the plane was headed back to Beijing. When he inquired, he said, flight attendants told him it was a map display error.
"The captain notified us (of the reason) after we safely landed," he wrote on Sina Weibo, China's equivalent of Twitter.
Another passenger, whose Weibo name is Nataliebu, said crew members only told passengers to buckle up and sit tight due to strong air turbulence.
On June 29, passengers and crew members thwarted a hijack attempt on a short-haul flight within the far western Chinese province of Xinjiang. Authorities said six ethnic Uyghur men tried to take control of the plane through violence before being subdued. The plane returned to its origin safely.
Security is usually tight throughout Beijing Capital International Airport, the world's second-busiest air hub after Hartsfield-Jackson International in Atlanta. More than 78 million passengers passed through the Beijing airport's three terminals last year.