U.S. Trade Representative Robert Lighthizer testifies before House Ways and Means Committee hearing on "U.S.-China Trade” on Capitol Hill in Washington U.S., February 27, 2019. REUTERS/Kevin Lamarque

WASHINGTON (Reuters) - The United States is seeking to prevent China from competitively devaluing its currency as part of ongoing trade talks between the countries, following past manipulations of the yuan, U.S. Trade Representative Robert Lighthizer said on Wednesday.

Speaking to members of Congress, Lighthizer also said it would be a catastrophe for lawmakers to not approve the United States-Mexico-Canada Agreement (USMCA) trade deal, adding that he expects a Federal Register notice formally delaying tariff hikes on Chinese goods in the coming days.