A United flight en route to Denver from Anchorage, Alaska, was diverted on Saturday to Vancouver where a suspect was arrested due to "security concerns," authorities said.

United Air Lines Flight 1104 landed safely at about 4:30 a.m. (1230 GMT) in the western Canadian city, where it was met by law enforcement authorities, the airline said. There were 131 passengers and six crew members aboard the Boeing 737.

The Royal Canadian Mounted Police in Richmond, British Columbia, said on Twitter a suspect was taken into custody but operations at Vancouver International Airport were not affected.

RCMP Corporal Dennis Hwang said a male U.S. citizen was in custody and police were "working towards laying charges".

"I would not classify it as a terror issue but certain security protocols came into play once we received the call," he said from Vancouver.

CNN reported that a "threatening message" was found on the aircraft. Hwang declined to give details. – Reuters