(File photo)

A Delta Airlines flight from Seattle to Beijing returned to the airport on Thursday less than one hour after takeoff after a passenger reportedly assaulted a flight attendant.

Several passengers helped restrain the attacker after he assaulted a flight attendant in the first class area some 45 minutes after takeoff. A cabin crew member and two passengers were injured. The severity of their injuries remain unclear, Sea-Tac Airport spokesperson Perry Cooper said.

According to an eyewitness surnamed Lin, most of the passengers were Chinese. All of them were terrified by the attack. Lin claimed he saw a Chinese man trying to fight the attacker, allegedly a white male, as the attacker tried to enter the cockpit. “He [the Chinese man] came back wounded. There was blood on his body,” Lin was quoted as saying by China National Radio.

Cooper denied reports claiming the attacker tried to enter the cockpit, The Washington Post reported.

In a reply to Thepaper.cn, Cooper said it is too early to consider the incident a national security threat. The passenger was removed from the flight by US law enforcement for further investigation. The FBI is also involved in the investigation.

According to Flightrardar24, a live flight tracker, the plane had already reached Canada when the attack took place.

(Photo/Thepaper.cn)

Delta Airlines said that Flight 129 would take off again and is expected to arrive in Beijing at 2 am on July 8, local time.

“The passenger was restrained onboard and was removed from the flight by law enforcement without further incident when the aircraft arrived back in Seattle,” a Delta spokeswoman said in a statement to The Washington Post.