The U.S. and Mexico are prepared to move ahead alone on a new trade agreement, and Canada may get left behind, a top White House official said Friday.

Kevin Hassett, chairman of the Council of Economic Advisers, told Fox News that the revised NAFTA agreement could end up being a bilateral rather than trilateral agreement if Canada doesn't come around soon.

"We're still talking to Canada. We're getting very, very close to the deadline where we're going to have to move ahead with Mexico all by themselves," Hassett said. "I'm a little surprised that the Canadians haven't signed up yet. They've got a really, really good deal that they should be participating in."

The deadline for Canada to come on board is likely Sept. 30, Hassett said at a Yahoo Finance conference Thursday in New York.

 Wilbur Ross: US advancing NAFTA talks with just Mexico    Wilbur Ross: US advancing NAFTA talks with just Mexico  

10:49 AM ET Tue, 18 Sept 2018 | 00:40

The pact between the U.S. and Mexico, agreed to in late August, contains significant provisions on measures including intellectual property theft and trade secrets.

Negotiations with Canada, though, have been trickier, with disputes over agriculture and dairy products believed to be unresolved. The new NAFTA could be a template for negotiations with China, which remains the key sticking point in the White House's desire to revamp global trade agreements.

Hassett said the U.S. has made a fair offer to Canada and is awaiting a response.

"I worry that politics in Canada is trumping common sense, because there's a very good deal that was designed by Mexico and the U.S. to appeal to Canada and they're not signing up, and it's got everybody over here a little bit puzzled," he said. "Hopefully at the last minute they come in, but if they don't we'll just move ahead with Mexico and we'll get Canada fixed a little bit later."

This was not the first time the White House has said it is prepared to move ahead without Canada — Treasury Secretary Steven Mnuchin told CNBC in late August that it was a possibility.

But Hassett's remarks still seemed to take a slight bit of steam out of what appears to be another positive day on Wall Street. Major averages were mixed.