Canada and the United States may be headed back to the World Trade Organization’s dispute court, this time over a disagreement about British Columbian wine.

The United States Trade Representative said Wednesday a WTO challenge has been triggered because of B.C. regulations amended in April 2015 that allow for the sale of wine in provincial grocery stores. Those rules, which limit which stores can sell imported wines, “intentionally undermine free and fair competition” and violate international trade rules, U.S. officials said.

“American winemakers produce some of the highest-quality, most popular wines in the world. When U.S. wine producers have a fair shot at competing on a level playing field, they can compete and win in markets around the globe,” said U.S. Trade Secretary Michael Froman.

“Canada and all Canadian provinces, including B.C., must play by the rules. This Administration is continuing to fight to level the playing field for American producers and workers, so that we can continue to grow our economy and support quality jobs across the United States.”

In an email, Canada’s Global Affairs department said the American complaint was on the official radar.

“We are aware of U.S. concerns related to the distribution and sale of wine in B.C. Canada takes its international trade commitments very seriously and gives careful consideration to a request for consultations from any WTO member,” the department said.

Canada and the United States will now enter consultations to try and come to an agreement, the USTR said. Failing that, Froman’s office said the Americans will consider a request for a formal dispute resolution panel be struck.

Trade experts close to the file had expected the challenge would be launched in the early days of the incoming Trump administration, said iPolitics columnist and international trade specialist Peter Clark.

British Columbia’s new wine regulations are a two-tiered model. They distinguish between grocery stores where there is a separate entrance and section to the liquor supply, known as the “store-within-store” model and grocery stores where the wine is simply sold off the shelf – sales that are restricted to only British Columbian wine.

Imported wine from places like California can be sold only in the store-within-store model.

“Public reports indicate that a number of grocery stores are already selling BC wine on their shelves under the ‘wine on shelf’ option,” the USTR said. “We are not aware of any grocery stores selling wine pursuant to the more costly “store within a store” option.”

Wednesday’s WTO challenge is the 26th trade dispute battle undertaken by the outgoing Obama administration.