An officer for Bishop International Airport was stabbed Wednesday in a possible terror-related incident in Flint, Michigan, sources told NBC News.

The attacker allegedly shouted "Allahu akbar" before stabbing Lieutenant Jeff Neville, who was bleeding from the neck, sources and witnesses at Bishop International Airport said.

Neville, a father of two who has worked at the airport since approximately 2000, is a member of the airport's Department of Public Safety and a retired Genesee County Sheriff’s Department lieutenant.

Law enforcement officials said the suspect is from Quebec and has a Canadian passport.

VIDEO: Michigan airport stabbing of officer appears to be terrorism

But the stabbing happened outside of the TSA area, meaning the suspect did not get through security with a knife, four senior law enforcement officers told NBC News.

In a statement released by the FBI, officials said it is still too early to determine what motivated the attack, but that they were questioning the suspect.

"We are aware of reports that the attacker made statements immediately prior to or while attacking the officer, but it is too early to determine the nature of these alleged statements or whether or not this was an act of terrorism," the statement reads.

Officials said that they believe the attack was an isolated incident and that there is "no specific, credible" threat to the Flint community.

Michigan State Police initially tweeted that the officer was in critical condition. Just after 1 p.m., officials confirmed Neville was out of surgery and was upgraded to stable condition.

“I spoke with his family up at the hospital, and he had completed surgery," Genesee County Commissioner Mark Young told NBC News. "He was still in recovery when I left the hospital.”

Young — whose 35-year friendship with Neville began when the two worked at the Genesee Sheriff's Office — said while everyone is relieved the officer is alright, the situation is still tragic.

“I’d say we are feeling relieved that he’s in stable condition. This is something that police officers across the country — this is the Damocles that sits over every officer when they go out every day," Young said.

Neville had a successful career at the sheriff's office, Young said, earning several awards before climbing the ranks with the airport police.

“[Neville is] probably one of the nicest individuals you'd ever meet. He’s always quick to help and try to help people who have problems," Young said. "I literally don’t know anyone more like that then him.”

Authorities said the FBI was leading the investigation and tweeted that the airport had been closed after the stabbing.

It has since re-opened, according to the Federal Aviation Administration.

Bishop International's Facebook page posted that travelers inside the airport had been safely evacuated.

Witness Ken Brown told The Flint Journal that he was dropping off his daughter at the airport and saw the officer after he was stabbed. He said he saw a man detained by police and a knife on the ground.

"The cop was on his hands and knees bleeding from his neck," Brown said. "I said they need to get him a towel."

K-9 units were seen outside the airport after the stabbing as officers checked vehicles in the airport parking lot.

In a statement, Canada denounced the attack on Neville and said its law enforcement agencies were in touch with "their U.S. counterparts."

"Canada condemns this heinous and cowardly act. Our thoughts and sympathies are with the officer and his loved ones," a statement from the Canadian Embassy said.

The suspect was in custody, according to a press release from Flint City Hall, where security had been increased as a precaution. City Hall is approximately five miles away from the airport.

“Right now we are still awaiting more information about the situation at Bishop Airport this morning,” Mayor Karen Weaver said in a statement. “My thoughts and prayers are with all of our law enforcement officers who work to service and protect us each and every day."

Michigan Governor Rick Snyder sent his thoughts to Neville in a tweet.