U.S. House of Representatives' Speaker Nancy Pelosi said on Wednesday she hoped Congress would still be able to work with the White House to approve the U.S.-Mexico-Canada trade pact despite an impeachment inquiry centering on the president.

"They have nothing to do with each other," Pelosi told reporters. "The president has said he wants this U.S.-Mexico-Canada trade agreement to go forward. ... Does it mean that he can't do that? That's really up to him."

As a presidential candidate, President Donald Trump promised to renegotiate the North American Free Trade Agreement (NAFTA) in favor of a better trade deal with Mexico and Canada. But House Democrats have called for changes to be made in the replacement pact before its approval, including more guarantees of labor enforcement standards in Mexico.

Trump has said the House's impeachment inquiry, which centers on his request for Ukraine's President Volodymyr Zelinskiy to investigate Trump's political rival, Democratic former Vice President Joe Biden, could imperil the trade pact.

Pelosi said progress had been made toward securing congressional approval of the U.S.-Mexico-Canada trade pact, but stressed there was still work left to do.

"When we can arrive at a place where not only do we have our issues addressed but that we have enforceability that will make it real for America's families and farmers, then we can go down that path," Pelosi said.