Mexican and Canadian officials are serious about their countries not ratifying the proposed United States-Mexico-Canada trade agreement unless the Trump administration ends steel and aluminum tariffs on their products, Senate Finance Chairman Charles E. Grassley said Tuesday.

Grassley, R-Iowa, said the Mexican ambassador and the Canadian Foreign Affairs minister in meetings last week with him reaffirmed their countries’ opposition to the continuation of the 25 percent steel tariff and the 10 percent levy on aluminum imports.

“The Senate in Mexico is not going to take it up until the tariffs are off and the House of Commons in Canada is not going to take it up if it is not there soon after March 1 and it’s not going to be there unless the tariffs are off,” Grassley told reporters during his weekly conference call.

The United States ended exclusions from the tariffs in June 2018 for both countries during talks that led to the proposed agreement, which would replace the 1994 North American Free Trade Agreement if all three countries approve it.

The demand from both countries is just the latest hitch facing the trade agreement. Some congressional Democrats have raised the possibility of new talks to address their concerns about the enforcement of labor, environmental and prescription drug provisions.