FLINT, Michigan - A Canadian man from Tunisia shouted in Arabic before stabbing a police officer in the neck at a Michigan airport on Wednesday, is now being investigated as an act of terrorism, federal and court officials said.

Amor Ftouhi, 49, of Montreal, was immediately taken into custody. A criminal complaint charging him with committing violence at an airport, said Ftouhi asked an officer who subdued him why the officer didn't kill him.

The attack at Bishop International Airport in Flint, Michigan, is being investigated as an act of terrorism, but authorities have no indication at this time that the suspect was involved in a "wider plot", said FBI Special Agent in Charge David Gelios.

"At this time we view him as a lone-wolf attacker," Gelios said. "We have no information to suggest any training."

The criminal complaint said Ftouhi stabbed airport police Lieutenant Jeff Neville with a 30-centimeter knife after yelling "Allahu akbar", the Arabic phrase for "God is great". According to the FBI, Ftouhi said something similar to "you have killed people in Syria, Iraq, and Afghanistan, and we are all going to die."

More charges against Ftouhi could be filed as prosecutors take the case to a grand jury seeking an indictment, Gelios said. The Flint Journal, citing court officials, said that Ftouhi is a dual citizen of Canada and Tunisia.

Neville was in satisfactory condition after initially being in critical condition, airport police Chief Chris Miller said.

Canadian charged

Ftouhi appeared in federal court in Flint to hear the charge and will get a court-appointed attorney. A court spokesman said Ftouhi will remain in custody until a bond hearing next Wednesday.

The attack occurred just before 10 am, prompting officials to evacuate and shut down the airport and add security elsewhere in the Michigan city about 80 kilometers northwest of Detroit. White House press secretary Sean Spicer said President Donald Trump was briefed on the stabbing, and US Attorney General Jeff Sessions said he was "proud of the swift response" by authorities from both the US and Canada.

Police in Canada were searching a Montreal apartment. Police spokesman Benoit Boiselle said officers with their department were assisting the Royal Canadian Mounted Police in the search on behalf of an FBI request.

Boiselle said three people staying at the residence had been taken in for questioning.

Luciano Piazza, the building landlord, said Ftouhi was not a difficult tenant and that he is married with children.

"I never had any problems with him," Piazza said. "I'm really surprised. I would see him at least once a month, when he paid his rent."

Gelios said Ftouhi legally entered the US at Champlain, New York, on June 16, and made his way to the Flint airport on Wednesday morning.

Ap - Xinhua