Photo: CTV News

Two security guards have been injured in an explosion that occurred during an overnight armed holdup at a Scotiabank branch in northeast Edmonton.

Police at the scene say the guards — a man and a woman believed to be employed by GardaWorld — suffered significant head and facial injuries in the blast that occurred around 2 a.m.

They also say the guards were involved in some sort of confrontation with a male armed with a gun, who got away with a bag of money and is still being sought.

Karan Singh, a clerk at a convenience store across the street, told CTV Edmonton that he was working at the rear of the store when he heard what sounded like a blast.

"I was sitting back in the room and there were two explosions. After that, one of my customers told me that down the street there were people screaming out there."

Early-morning commuters were being asked to avoid the area while police investigated.

This is the second explosion at an Edmonton bank in about three months.

Early on the morning of Sept. 19, police were called to a south-end RBC branch after an improvised explosive device, also known as an IED, went off inside the bank’s vestibule.

Police said at the time that two security guards had just arrived at the bank when the blast happened. Both were treated at the scene, then taken to hospital for precautionary reasons.

Investigators treated the explosion as an attempted robbery, but no money was stolen.