Police investigators walk into the residence of Amor Ftouhi, in Montreal, Quebec, Canada, June 21, 2017. Ftouhi has been identified as a suspect by the FBI in the stabbing of a police officer inside the main terminal of a small airport in Flint, Michigan. [Photo/Agencies]

CHICAGO - The FBI has identified the suspect in the Michigan airport stabbing on Wednesday as a Canadian resident and is investigating the case as an act of terrorism.

The suspect is 50-year-old Amor Ftouhi, who entered the US on June 16, FBI special investigator David Gelios told a televised press conference in Flint, Michigan State.

According to the FBI officer, Ftouhi yelled "Allahu Akbar", or "Allah is the greatest" in English before he made the attack with a 30-centimeter knife against Officer Jeff Neville, at the Bishop International Airport in Flint.

Michigan State Police said Neville was in "satisfactory condition" after surgery.

The FBI said the suspect was in custody and was being questioned, adding they were investigating the attack with the help of their Canadian counterparts.

Gelios told reporters that Amor Ftouhi arrived at the airport on Wednesday morning and spent some time on the first floor and went to a restaurant on the second floor.

He then came out from a restroom and pulled out the knife, starting to stab the officer in the neck.

Ftouhi also said something like "you have killed people in Syria, Iraq and Afghanistan" and "we are all going to die," according to initial accounts from eye witnesses.

At this stage, FBI treated the incident as a "lone-wolf" attack, said Gelios.