Canadian Foreign Minister Chrystia Freeland on Wednesday said officials needed to do more work before she could hold fresh talks with the United States on renewing NAFTA as time runs out to reach a deal.

A well-placed source had earlier told Reuters that Freeland planned to return to Washington for more talks on Thursday with U.S. Trade Representative Robert Lighthizer, adding that plenty of work remained.

But Freeland, who briefed Prime Minister Justin Trudeau about the negotiations twice in a matter of hours on Wednesday, said she had agreed during a phone conversation with Lighthizer that she would stay in Canada.

“We decided that in order to have another productive conversation, it would be best to give our officials some time to hold technical discussions,” she told reporters late in the day, but gave no details.

U.S. President Donald Trump has already struck a deal with Mexico, the third member of the North American Free Trade Agreement, and is threatening to exclude Canada unless Ottawa agrees to concessions.

Canada and the United States are still arguing over cultural protections, an American demand for more access to the Canadian dairy market and a dispute resolution mechanism that Canada wants to keep and Washington insists be scrapped.