FLINT, Mich. - A Quebec man entered an airport in Michigan on Wednesday morning, yelled 'Allahu akbar' and stabbed a security officer in the neck, according to U.S. federal prosecutors who said they are investigating the incident as an act of terrorism.

Amor Ftouhi, 49, was arrested shortly after the incident and was charged with committing violence at an airport, FBI special agent in charge David Gelios told a news conference.

Gelios said the incident happened at 9:45 a.m. at the Bishop International Airport in Flint, about 80 kilometres northwest of Detroit.

Ftouhi entered the United States legally in Lake Champlain, N.Y., on June 16 and made his way to Flint on Wednesday morning, he said.

“We do know Mr. Ftouhi entered the airport, he spent a little time on the first level, then he went upstairs he spent some time in the restaurant up there,” Gelios said.

“Then he came out, he was carrying baggage. He went into a restroom. He spent a little time in the restroom. Dropped both bags and came out, pulled out a knife, yelled 'Allahu akbar,' and stabbed Lt. Neville in the neck.”

Lt. Jeff Neville with the Bishop International Airport police underwent surgery and his condition has been upgraded from critical to stable, said Michigan State Police Lt. Mike Shaw.

Authorities said they have no indication at this time that Ftouhi was involved in a “wider plot,” but the investigation is in its early stages.

The criminal complaint says Ftouhi stabbed Neville with a large knife and declared “Allahu akbar,” the Arabic phrase for “God is great.” The FBI, which is leading the investigation, said Ftouhi said something similar to “you have killed people in Syria, Iraq, and Afghanistan, and we are all going to die.”

“As we progress and take this matter to grand jury for indictment, other charges could be pending later on,” Gelios said. “It's an ongoing investigation, there are joint operations going on in Canada as we speak. We want to thank our Canadian partners who are helping us further investigate this attack.”

Public Safety Minister Ralph Goodale called the incident a “heinous and cowardly attack.”

“There is complete co-operation between the RCMP and other Canadian authorities and agencies with all of their counterparts in the United States and we will do everything we possibly can to assist in this matter,” Goodale told reporters in Ottawa.

U.S. Attorney General Jeff Sessions said in a statement that he is “proud of the swift response” by authorities from both nations.

He said the attack is being investigated as an act of terrorism and added it will be “prosecuted to the fullest extent of the law.”

Canadian TV footage showed police escorting at least one person away from a four-storey Montreal apartment building where the suspect is believed to have lived. There was a significant police presence outside the building.

City police spokesman Benoit Boiselle said officers with the department were assisting the RCMP in a search of the apartment.

He said the FBI requested the search after the attack.

Meanwhile, witnesses in Flint 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 local media.

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

Montreal police spokesman Benoit Boiselle said officers with the department are assisting the RCMP in a search of an apartment in the city.

Boiselle said the FBI requested the search after the attack.

A number of police stood guard outside of the apartment building in the east end of Montreal. It's located on Belair St. in St-Michel borough.