MONTREAL -- Work on a major bridge connected to the Island of Montreal will be carried out around the clock, officials say, but they're giving no timeline on when it might reopen.

Transport Minister Francois Bonnardel says damage to Ile-aux-Tourtes Bridge was caused by drilling work that made the bridge's reinforcement bars deteriorate.

"It's human, what happened," he said. "We found on April 30 that a reinforcement bar -- 32-millimetre reinforcement bar -- had been damaged."

One lane of the bridge was closed, but then further drilling on May 12 caused more damage.

"We saw that more bars had been damaged with the drilling," said Bonnardel in a press briefing a day after the bridge's emergency closure on May 20.

Though the company tasked with carrying out the work caused the breakage, Bonnardel stated it will continue the work, calling them a "good entrepreneur."

"Something happens when you make an error and we have to deal with it. Right now, it's not to tell them 'it's your fault,'" he said.

"We have to work together as fast as possible to reopen this bridge rapidly."

Bonnardel says every effort was made to keep the Ile-aux-Tourtes bridge safe and open until it was scheduled to be replaced in 2027.

Nevertheless, the complete closure of the bridge, which links Vaudreuil-Dorion to Senneville just west of Montreal, was closed suddenly on Thursday evening, causing major congestion.

Bonnardel confirms work will be carried out 24 hours a day, seven days a week, but he could not give a definite timeline as to when the bridge will reopen.

"I'm asking you to give us some time," he said.

This decision was deemed the only possible option to ensure the safety of the bridge's approximately 87,000 daily users. 

Traffic was heavy on Highway 20 from Ile-Perrot to Sainte-Anne-de-Bellevue Friday morning, one of the only other alternate routes to the Island of Montreal.

The bridge, which is part of Highway 40, is 56 years old. But the closure was still preventative, and normally it could have lasted until the new construction, Bonnardel said.

"If we had to close the bridge yesterday, it was not due to a lack of maintenance, but rather because damage was found on reinforcement bars, which are steel rods, used to make concrete more resistant," he said.

"Closing the bridge was the only responsible decision that could be taken."

To compensate, the government says it has removed the toll on Highway 30 until the bridge reopens.

In addition, service will be free on the exo1 Vaudreuil-Hudson commuter train line and police officers will be deployed to assist with traffic.

-- with files from The Canadian Press.