Police have arrested a suspect after a stabbing spree in an Edmonton grocery warehouse that left two people dead and four others injured.

A man entered the Loblaw warehouse shortly after 2 p.m. dressed in combat gear and armed with a knife in each hand, police said.

"Upon our arrival we discovered numerous people suffering from serious stab wounds," acting Insp. Malcom Allan told reporters at the scene.

Allan said six victims were taken to hospital.

Two of the stabbing victims suffered serious injuries and two others suffered non-life-threatening injuries.

"We found victims throughout the complex," he said, adding that police searched the expansive building twice to look for victims.

While investigators haven't identified a motivation behind the stabbings, they believe the suspect may have planned the attack.

"He wore some sort of load bearing vest, or body armour, during this incident," Allan said during a press conference Friday evening. "That suggests there may have been some pre-planning."

Police have arrested 29-year-old Jayme Pasieka in connection with the stabbings, and say he is a warehouse employee.

Immediately following the stabbings, the suspect fled the scene in a 1999 green Ford Explorer.

A citizen spotted the suspect in Edmonton's south-east end and alerted police, who arrested him a few hours after the stabbings took place.

Investigators say the crime scene is "expansive."

"It’s a complex scene," Allan said. "This gentleman, it’s alleged he went on a bit of a rampage inside of there."

Police said all the victims are believed to be warehouse employees.

"There are a lot of traumatized people," Allan said of the multiple warehouse employees who witnessed the attack. "We're trying to help these individuals as best as we can."

One witness at the scene said that after leaving the building, the suspect approached his car.

"Unfortunately, his car was parked right beside mine he said, 'Do you want to get stabbed,'" the man said.

Another witness said he saw a "crazed guy" coming out of the building with a knife in each hand.

"Everybody just ran," he said.