A bus driver rammed his vehicle into a day care center near Montreal Wednesday, killing two four-year-old children in what police believe was a deliberate act.

One child died on the scene and another in an ambulance, Canadian authorities said, after several children were trapped under the vehicle when it slammed into the building in the suburb of Laval at around 8:30 am (1330 GMT).

"We think that this is deliberate, but we don't know the motive," local police chief Pierre Brochet told AFP.

The 51-year-old suspect, named as Pierre Ny St-Amand, seemed agitated as he appeared via video link in court later Wednesday. He faces nine counts including premeditated murder and attempted murder.

Six other children transported to the hospital are out of danger, said Laval police spokeswoman Erika Landry.

Hamdi Ben Chaabane, who lives nearby, said he arrived at the scene to find the driver acting erratically.

"He opened the door. He took off all his clothes. He was totally naked," Chaabane said, according to broadcaster CBC.

"We don't know why he did that. We dove on him. We tried to subdue him," he said, describing the man as "in another world."
St-Amand refused to speak but nodded to answer the judge's questions during his court appearance, smiling broadly and repeatedly trying to sit up from the bed to which he was handcuffed, an AFP journalist in the room observed.

The case will resume on February 17, crown prosecutor Karine Dalphond said, with St-Amand remaining in a psychiatric hospital in the meantime.

The bus he drove appeared to have smashed into a side of the building which is near a parking lot away from the nearest road, remaining there late Wednesday afternoon with part of the roof collapsed on its front portion.

Another parent at the scene, holding her own child, told Radio Canada it was the center's class of oldest children that was hit.

"I know that there are no words for parents who have lost their children this way," Prime Minister Justin Trudeau told reporters.

"All Canadians are grieving with them, and we'll do whatever we can to support them in their horrific pain in the coming days, months and years of grief," he said.

No adults were hurt in the collision.