FLINT, Mich. (AP) — The FBI is looking at terrorism as a possible motive after an officer was stabbed in the neck at the Flint airport, a law enforcement official said after the Wednesday attack that prompted an evacuation and beefed up security elsewhere in the Michigan city.

A second law enforcement official said authorities were investigating witness reports that the suspect made statements during the incident at Bishop International Airport, including saying “Allahu akbar,” the Arabic phrase for “God is great.” Both officials spoke on the condition of anonymity because they weren’t able to publicly discuss the incident. White House press secretary Sean Spicer said President Donald Trump was briefed on the stabbing.

The condition of the officer who was stabbed, airport police Lt. Jeff Neville, was upgraded from critical to stable by Wednesday afternoon, Michigan State Police Lt. Mike Shaw said. Shaw said one person is in custody and nobody else is believed to have been involved.

Shaw said “everything is on the table” as far as motive is concerned but cautioned against jumping to conclusions. The FBI is leading the investigation. The primarily regional airport, which had been evacuated, is “shut down and secure,” Shaw said, and no other threats had been identified.

In an official statement, the FBI said it’s aware of the reports that an attacker made statements during the stabbing, but added that it’s too early to determine their nature or whether the incident was an act of terrorism.

Witnesses described seeing the suspect led away in handcuffs by police, Neville bleeding and a knife on the ground.

“The cop was on his hands and knees bleeding from his neck,” Ken Brown told The Flint Journal. “I said they need to get him a towel.”

Cherie Carpenter, who was awaiting a flight to Texas to see her new grandchild, told Flint TV station WJRT she saw the attacker being led away in handcuffs. She described the man in custody as appearing “blank, just totally blank.”

Flint officials said they stationed police officers around City Hall after the incident a few miles away. Mayor Karen Weaver said in a release Wednesday “the situation is under control” but officials sought to take “extra precautions.”

Flint is about 50 miles northwest of Detroit.

Karoub reported from Detroit. Associated Press writers Sadie Gurman in Phoenix, Arizona, and Kenneth Thomas in Washington contributed to this story.