A shooting that sent four people to hospital and another gun-related incident forced thousands of students at two Montreal area colleges to go into lockdown on Friday.
At 5:30 pm local time (2230 GMT), gunshots rang out at a park across the street from Montmorency College in the Montreal suburb of Laval, police spokeswoman Genevieve Major told AFP.
Four people who had been shot sought refuge at the college and were later taken to hospital with non-life-threatening injuries.
The college, which is attended by nearly 10,000 students and faculty, remained locked down into the evening as police swarmed the area in search of the shooter.
Mayor Stephane Boyer tweeted that a police operation was "underway", while television footage showed parents of students crowding the roads around the college after they rushed to the scene.
Earlier, a 19-year-old man wearing a bulletproof vest was arrested at a junior college 40 kilometers (25 miles) south of Montreal and charged with allegedly uttering threats.
Students and staff at the Cegep Saint-Jean-sur-Richelieu told local media they were ordered to barricade themselves in classrooms and turn off the lights for most of the day, while a police operation unfolded outside.
"At the beginning we were very scared," student Alejandra Montequin told Canadian broadcaster Global News. "It was very tense, people were talking to their parents."
Quebec Public Security Minister Francois Bonnardel said in a Twitter post that the students in Saint-Jean-sur-Richelieu had "experienced a difficult situation today."
"I'm relieved at the turn of events," he said, adding that he would wait for the results of the police investigation "to fully understand what happened."