Construction on a multibillion-dollar bridge touted as a key link between Canada and the United States is officially underway, Prime Minister Justin Trudeau said Friday.

Flanked by dignitaries from both sides of the border, the prime minister said the Gordie Howe International Bridge, currently slated to cost $5.7 billion, will be built over the next six years and be ready for operation by late 2024. He made the announcement at the beginning of a jam-packed day in Windsor, Ont.

He said the 2.5-kilometre bridge spanning the Detroit River will provide a critical conduit for commerce between the two countries, an issue he said has taken on increased relevance since the successful resolution of contentious free trade negotiations earlier in the week.

"I'm confident that integrated, two-way trade between Windsor and Detroit will only increase from here, which is a great thing for local communities and the national economy," Trudeau said. "Shorter travel times, more efficient supply chains and better access to the U.S. market. The Gordie Howe International Bridge has been a long time coming."

Trudeau said the bridge was always a priority project, but has taken on added significance since Canada joined the U.S. and Mexico in signing an agreement-in-principle on a free trade deal. The pact, dubbed the U.S.-Mexico-Canada Agreement, has yet to be formally ratified.

The road to Friday's announcement has been strewn with political potholes that proponents have had to navigate at the state and federal levels.

The bridge has also survived multiple legal challenges from the private owner of the nearby Ambassador Bridge, who publicly appealed to U.S. President Donald Trump this year to revoke a presidential permit Barack Obama granted to greenlight construction.

On Friday, the bridge received a public benediction from Michigan's Republican Gov. Rick Snyder.

"This is a friendship of many, many years, and what better representation than the Gordie Howe International Bridge," he said. "Gordie Howe...set the benchmark for the hockey world. This bridge will set that benchmark for the Canadian-American relationship and for the rest of the world."

Trudeau said the construction project will create an estimated 2,500 jobs and will lead to more sustained employment growth once completed.

He also touted the long-term trade benefits, saying a quarter of all trade passes through the Windsor-Detroit corridor while 7,000 commercial vehicles travel through the area daily.

The six-lane, cable-stayed bridge -- whose towers will be designed to look like a hockey stick taking a slap shot -- is expected to have a lifespan of 125 years.

Later on Friday, Trudeau is expected to meet with union leaders, tour a vehicle assembly plant and hand out turkeys for Thanksgiving.