(NewsNation Now) — Trucker protests over vaccine mandates continued Wednesday morning at the U.S.-Canadian border. The stoppage has caused disruptions to a major U.S. trade route.

The Ambassador Bridge between Windsor, Ontario and Detroit carries about a quarter of the trade between the United States and Canada. At least three ports of entry are affected by the protest.

The “Freedom Convoy” consisting of truckers and other motorists started as a movement opposing a Canadian vaccine mandate for cross-border drivers, a requirement mirrored by a U.S. rule, but has morphed into a rallying point against the prime minister’s public health measures.

The convoy started in British Columbia and has evolved into widespread expressions of discontent. Protests have even spilled over into the United States from Michigan to Montana.

In Canada, the government is calling the movement an occupation because downtown Ottawa is at a complete gridlock. Protesters have said they will not leave until all vaccine mandates and COVID-19 restrictions are lifted. They also called for the removal of Justin Trudeau’s government, though it is responsible for few of the restrictive measures, most of which were put in place by provincial governments.

In the U.S. online chatter is growing about a similar demonstration, but no route or time has been announced. The White House says it’s monitoring northern border activity and the possibility of the convoy moving to the states.

Protesters have gathered in Canada for at least 10 days. It’s unclear how the shutdown will affect the U.S. supply chain or how long the closure will last.

The Ambassador Bridge is used by nearly 40,000 commuters, tourists and truck drivers carrying $323 million worth of goods between the U.S. and Canada every day, according to the website for the bridge.