The Montreal man accused of stabbing a police officer in the neck at an airport in Flint, Mich., last month has pleaded not guilty to two charges that could land him in prison for life.

Amor Ftouhi stood in U.S. federal court Wednesday and refused to state whether he pleaded guilty or not, forcing the judge to enter a not-guilty plea, according to David Ashenfelter, public information officer at U.S. District Court for Eastern Michigan.

Ftouhi, a 49-year old native of Tunisia, was arraigned Wednesday in federal court on charges of committing an act of violence at an international airport and interfering with airport security.

The charges carry a maximum penalty of life in prison.

Ftouhi was arrested June 21 when he pulled out a long knife with a serrated edge and attacked Lt. Jeff Neville at Bishop International Airport.

A police dog and handler search cars in a parking lot at Bishop International Airport in Flint, Mich., after the stabbing last month. (Jake May/The Flint Journal-MLive.com/Associated Press)

Authorities say Ftouhi referenced killings in Syria, Iraq and Afghanistan and yelled "Allahu akbar," the Arabic phrase for "God is great" during the attack.

Authorities in both Canada and the U.S. treated the attack as a terrorist incident. The FBI investigated in Michigan while police in Montreal swarmed Ftouhi's St-Michel neighbourhood.

The FBI believes the Montreal man crossed into the United States at Champlain, N.Y., on June 16 and arrived in Michigan two days later. Officials also say Ftouhi tried to buy a gun while in the U.S. but was rejected.

The airport heightened security following the stabbing. (Shannon Millard/Flint Journal-MLive.com/Associated Press)

Ftouhi walked into the airport around 9 a.m. ET on June 21 carrying two bags, but did not try to pass through security, according to the FBI. Within the hour, he went into a restroom and walked out without his bags.

He then allegedly pulled out a knife and attacked Neville, who fought back and helped take down his attacker with the help of other officers and a maintenance man.

Neville is recovering after the attack, despite having a 30-centimetre wound that doctors say narrowly missed nerves and major arteries. He was released from hospital last week.

In both his court appearances, Ftouhi was heard uttering the same Arabic phrase for "God is great" that he yelled during his attack.