WASHINGTON (Reuters) - The top U.S. trade negotiator said on Wednesday he is ready to work with lawmakers “sooner rather than later” to address concerns over a new North American pact, even as a leading Democrat outlined roadblocks to the deal’s approval.

U.S. Trade Representative Robert Lighthizer testifies before a Senate Finance Committee hearing on "The President's 2019 Trade Policy Agenda and the United States-Mexico-Canada Agreement" on Capitol Hill in Washington, U.S., June 18, 2019. REUTERS/Leah Millis

U.S. Trade Representative Robert Lighthizer said he believes Democratic lawmakers’ core concerns on enforcement of labor and environmental provisions in the United States-Mexico-Canada Agreement (USMCA) can be sorted out quickly. His comments came just hours after Democratic leader Nancy Pelosi said she still has many concerns over USMCA.

Opposition in Congress could prove a major hurdle for the pact, which the Trump administration hopes to claim as its first major trade deal victory ahead of the 2020 presidential election cycle.

President Donald Trump has said bad trade deals, including the North American Free Trade Agreement (NAFTA), have cost millions of American jobs and promised repeatedly on the campaign trail to overhaul them.

“In terms of coming to agreement with members, I could sit down in a half a day and work out the labor provision and the environmental provision,” Lighthizer said at a hearing of the House of Representatives Ways and Means Committee.

Democratic House speaker Pelosi said earlier on Wednesday that she sees several impediments to congressional approval of USMCA, including enforcement tools, labor and environmental protections and provisions on pharmaceuticals.

The deal cannot simply be “NAFTA with sugar on top,” Pelosi told reporters.

“There are good provisions in the bill, but if you don’t have enforcement, you just have provisions in a bill,” Pelosi said. She said Democrats have a potential proposal for enforcement and added pharmaceuticals are a “big issue”.

USMCA, which replaces NAFTA, was signed by the countries’ leaders in late 2018 but has yet to be ratified.

Canadian Prime Minister Justin Trudeau will to travel to Washington on Thursday to meet with Trump to discuss the deal’s ratification.

Wednesday was Lighthizer’s second appearance this week at a congressional hearing to address lawmakers’ concerns over Trump administration trade policy, including a trade war with China.

Lighthizer reaffirmed on Wednesday that he did not believe the agreement needed to be reopened to address Democrats’ concerns.

“Right now, we’re going to have a catastrophe if this doesn’t pass,” Lighthizer said.