Toronto International Airport says operations have now returned to normal after a fire broke out in Terminal 1 last night, causing panic and travel delays for thousands of passengers.

The fire started in the ceiling on the lower level of the terminal sometime before 6:30 p.m.

It was quickly extinguished, but the terminal filled with smoke, prompting an evacuation.

All U.S.-bound flights were cancelled last night, as well as some international flights.

Early Monday, stranded passengers could be seen sleeping in the terminal, waiting to catch a new flight Monday. There was also a massive backlog of arriving flights because of the fire.

The airport said early Monday that terminals 1 and 3 were operating normally, with the exception of departing flights to the United States from Terminal 1.

At around 10:30 a.m., the airport said that operations had returned to normal for all flights.