Six children and an adult who was in shock were taken to hospitals, the police said.
Dr. Marc Girard, director of professional services for the Centre Hospitalier Universitaire Sainte-Justine, a pediatric hospital in Montreal, said four children of preschool age, two boys and two girls, were taken there around midmorning. The children were conscious when they arrived, but were “obviously victims of trauma,” he said.
“They are currently under observation, their health obviously affected, but their lives are not currently in danger,” Dr. Girard told reporters at a news conference, speaking in French. “We’re in the first 24 hours. Of course, developments are often difficult to predict with children, but we will give these children the best care possible and allow them to recover as quickly as possible.”
The police said that a crisis center had been set up for parents and others, as horror spread throughout Quebec and Canada.
Prime Minister Justin Trudeau of Canada told reporters that there were “no words for parents who have lost their children this way.”
“All Canadians are grieving with them and will do whatever we can to support them in their horrific pain over the coming days and months and years,” Mr. Trudeau said.
Stéphane Boyer, the mayor of Laval, said on Twitter that he was at the scene, meeting with families.
“I am shocked by this news,” he wrote. “The investigation into this tragic series of events is ongoing. My support goes out to parents in these difficult times. Laval is wholeheartedly with you and will be there for you.”
François Legault, the Quebec premier, said he would travel to Laval on Thursday with opposition leaders to show support for grieving families and day care workers.
