The busiest U.S. border crossing in Quebec was closed Friday for almost four hours after being targeted by a bomb threat, creating lengthy delays at other crossings.

A threatening phone call was received around 9 a.m. and the border complex at Saint-Bernard-de-Lacolle evacuated shortly thereafter, said Sgt. Ingrid Asselin of the Sûreté du Québec.​

Police, firefighters and ambulances were at the border as a precautionary measure. The crossing is about 65 kilometres south of Montreal. 

All lanes of Highway 15 in the vicinity and Interstate Highway 87 on the U.S. side of the border were closed for several hours.

The border was reopened early afternoon after a search turned up nothing suspicious. Provincial police are investigating the source of the call.  

Border crossing line highway 221

Drivers were forced to find alternative border crossings. (CBC)

Long lines at nearby border crossings

During the search, travellers were detoured to alternate border crossings, including Lacolle routes 221 and Hemmingford.

Dozens of cars inched along for more than a kilometre towards the Highway 221 border crossing — the closest to Lacolle, but a much smaller complex.

"We've been waiting 35 minutes and we've still got a long way to go," said Roger Anger, who'd driven with Danielle Tremblay from Quebec City.

"We're on vacation. It's not so bad. We're not in a hurry," Tremblay added.

Jenn and Charlie McAvoy were on their way back to Long Island, New York, after watching their son Charlie McAvoy Jr. win a gold medal with team USA at the World Junior Hockey Championship in Montreal.

They were in good spirits despite the wait.

"We just hit a detour and this is where we ended up," said Jenn McAvoy, as the family debated whether they should try another crossing.

Charlie McAvoy said the family doesn't cross the border often.

"Only for hockey tournaments," he said.

Paula Barto goes over the border a couple of times a week to drop off invoices for work.

"Depending on how much I chit-chat, it takes about five to 10 minutes to get across the border," Barto said. "I've been sitting here in line for about an hour and a half."

"It means I get an easy day today," she laughed. "It means my boss will have to cover while I'm here."

Lacolle is among the busiest border crossings in Canada and is used by about two million people annually.

With files from Radio-Canada and Brennan Neill