Airports are returning to normal operations after Canada's air traffic control service said some received bomb threats early Thursday morning.
Nav Canada said the early morning threats affected airports in Ottawa, Montreal, Edmonton, Winnipeg, Calgary and Vancouver.
U.S. Federal Aviation Administration spokesperson Kevin Morris said in a statement there were "brief ground stops" at airports in Montreal and Ottawa, and they were lifted at around 7:40 a.m.
Nav Canada said in a social media post that service is gradually resuming after "the evacuation of number of our sites" and threat assessment by authorities.
"We thank airlines and passengers for their patience as we work towards normal operations," it said.
Transport Canada spokesperson Hicham Ayoun said the agency is working with airport authorities, Nav Canada and local law enforcement "to fully assess the situation."
"As a result of this morning's events, some flights may still be delayed over the next hours," Ayoun said in a statement.
The Ottawa airport announced to passengers a little after 10 a.m. that it was close to resuming normal operations.
The airport said earlier Thursday that it was investigating a "security incident" and operations could be disrupted. Its website showed that several flights were delayed.
An Ottawa airport spokesperson said it was investigating alongside city police and there was only a "small impact" on operations.
Austin De St. Croix said he was at the Ottawa airport Thursday and was heading to Vancouver when his flight was suddenly cancelled.
"I went to check in, and then between checking in and the security gate, they told me my flight was cancelled, no info," he said.
Lorraine Sundholn was also at the Ottawa airport Thursday and was set to fly Halifax before her flight was delayed.
"We just sit and listen to the announcements as they come up and where to go when they finally cancelled the flight," she said.
The Vancouver airport said it is "aware of a security concern" involving Nav Canada operations and other airports, and at this time its flights are operating normally.
"Safety and security remains our top priority and a thorough threat assessment was conducted," it said in a social media post.
Travellers are advised to check the status of their flight before heading to the airport.
Picture Courtesy: THE CANADIAN PRESS/Sean Kilpatrick