Amid indications that revisions to the United States-Mexico-Canada Agreement (USMCA) trade deal are close to completion, Donald Trump tweeted an attack on a senior Democrat in Congress.

If the House speaker, Nancy Pelosi, “doesn’t move quickly” to approve the deal, the president tweeted, it “will collapse!”

In contrast, a senior Mexican diplomat told reporters in Washington negotiators were close to concluding revisions.

“We’re getting close, I’m confident,” Jésus Seade, the deputy foreign minister for North America, told reporters outside the US trade representative’s office. He said he would probably return on Monday to continue talks.

On Friday evening, he had said many issues still needed to be resolved.

One point of contention is over steel, after the US trade representative, Robert Lighthizer, made a last-minute demand for a revised definition of what would constitute North American steel under automotive rules of origin.

Mexico approved the USMCA this year but US ratification has been held up by Democrats who have voiced concerns over the enforcement of labor and environmental provisions.

“Hard to believe,” Trump tweeted on Saturday, “but if Nancy Pelosi had put our great Trade Deal with Mexico and Canada, USMCA, up for a vote long ago, our economy would be even better. If she doesn’t move quickly, it will collapse!