A co-ordinated smoke-bomb attack crippled Montreal's subway system Thursday, cutting off service and creating a nightmarish morning commute.
Bombs were tossed onto the tracks during rush hour at three stations along the transit network that connects large swaths of the city.
It wasn't the first interruption to subway lines in recent weeks, as Montreal has dealt with unwieldy student protests.
But this one was notable.
Police said several bombs were set off between 7:45 a.m. and 8:30 a.m., sending clouds of smoke billowing through stations at key transfer points.
The stunt paralyzed all lines along the system.
Quebec Premier Jean Charest swiftly condemned the attack, saying he hoped the guilty parties would be found.
"It's inexplicable," Mr. Charest told reporters in Gatineau, Que., Thursday.
"There's no reason to commit acts of intimidation and violence. There's no excuse for this — none."
Police said they were hunting Thursday for several suspects: one man and three women.
They circulated photos of potential suspects — which police received from witnesses — in the hope of tracking down the suspects.
Above ground, the trickle-down effect was felt in the city's streets, with long lineups at bus stops and increased traffic under a heavy drizzle.
Packed city buses zoomed past stranded commuters desperate to find a way to get to work, school and appointments.
Some resorted to hitchhiking along the city's busy boulevards, while others hopped on bicycles for a rain-soaked ride to the office.
There were reports on social media of some incidents, like ambulances struggling to get through traffic.
Police did not immediately blame anyone for the disruption. They have repeatedly said in recent weeks that some radical groups have been taking advantage of students' anti-tuition battle to create their own damage.
An attempt to restart the system quickly failed, with another smoke attack reported, prompting authorities to declare yet another shutdown. Service began returning on a gradual basis after 9:30 a.m. and it was fully re-established after 10:40 a.m., but for many the damage was done.
Commuters vented their rage.
One listener wrote to local radio station CJAD to say that Premier Jean Charest should withdraw whatever offer he has made to students, and demand that the Army be called in. Other commenters on news websites likened it to domestic terrorism.
But there were also reports of civic-mindedness Thursday, with people offering rides and with a temporary increase in BIXI public-bicycle service.
Montreal police say the 911 emergency phone line was inundated with calls from citizens about smoke in the metro.
In the meantime, many locals waited calmly for service on the subway to resume.
"I've had to cancel a few things and push things later on in my day, so it kind of makes things frustrating," said Marlene Bambonye, as she took cover from the drizzle outside the cramped Laurier station, where people huddled inside.
"But, you know, it's kind of part of the city. So, you get used to it. You make do."