TORONTO -- The president of Toronto's police union said an officer's actions in arresting a suspect in Monday's deadly van attack without firing a single shot was "one shining moment" in an otherwise horrific day.

Mike McCormack of the Toronto Police Association said the arrest, caught on videos that have been widely circulated on social media, has served as a glimmer of hope for a city caught in tragedy.

"It's one shining moment in an absolutely game-changing, abysmal, horrific day in the city of Toronto," McCormack said in a phone interview Tuesday. "The one ... positive to take-away from that day was his behaviour."

At a news conference Tuesday, Toronto Police Chief Mark Saunders said he attributes the nonviolent resolution to de-escalation training.

But Saunders, who said he had spoken with the officer, said the handling of the situation was "nothing short of remarkable."

Police sources identified the officer as Const. Ken Lam, with the force's 32 Division.

With the city still on edge following Monday's incident, many social media users have hailed the officer as a paragon of restraint based on footage of his tense standoff with the alleged van driver. It happened not far from the stretch of Yonge Street where a van mounted a sidewalk and rammed into pedestrians, killing 10 and injuring 14.

In one of the videos of the arrest, a man, asking to be killed, stands by a damaged white rental van and points a dark object towards the officer. The officer refuses to shoot and repeatedly yells for the man to get down.

The suspect warns he has a gun in his pocket.

"Shoot me in the head," the man can be heard saying on the video.

From a highrise window, another video appears to show the suspect walking backwards with his arms raised as the officer moves toward him.

The suspect eventually goes to the ground and street-level footage shows the officer kneeling over him as he lies on the pavement.

"It could have gone either way. Any time if that threat escalated, we could have had a different outcome," McCormack said of the arrest.

"He reacted to what he was seeing, what his training taught him, and we're extremely proud of him. He may have prevented additional deaths."

McCormack said the officer was one of many first responders who ran towards the danger as the van mounted the sidewalk between Finch Avenue and Sheppard Avenue.

Officers pushed pedestrians out of the van's path, performed CPR and attended to "mangled" victims, said McCormack.

Even for seasoned officers, he said, the carnage was among the worst they had ever witnessed.

McCormack has been in touch with the officer, who he said is overwhelmed with emotion, but eager to get back on the streets.

"He's more concerned with the victims ... than what he has done."

McCormack said that while the officer maintains his actions were "no big deal," as the adrenaline fades, he will have to face the magnitude of what he's gone through.

"(There's) this whole notion that police officers go out and shoot first and ask questions later," he said. "Many times our officers are dealing with people in situations that's resolved in a peaceful way.

"It was demonstrated in an overwhelmingly clear fashion ... what police officers are really about, and what they really do."