U.S. Trade Representative Robert Lighthizer said progress on updating Nafta fell short of expectations during the latest negotiations and that time is running out for a new deal.

“Our time is running very short,” Lighthizer said during a ministerial briefing at the conclusion of the seventh round of talks in Mexico City on Monday. Campaigning will begin “in earnest” next month for Mexican presidential elections on July 1, while the Canadian provinces of Ontario and Quebec will hold elections this year and the U.S. will have a congressional mid-term vote, Lighthizer said. “All of these complicates our work,” he said.

“I feel the longer we proceed the more political headwinds we will feel,” Lighthizer said.

The U.S. would prefer hammering out a deal with Mexico and Canada but if those talks fail the Trump administration would consider separate bilateral deals, said Lighthizer. Canada’s Foreign Minister Chrystia Freeland, speaking at the briefing, said there’s been solid progress toward a deal.