"We are within range of a substantially improved agreement for America's workers. Now, we need to see our progress in writing from the Trade Representative for final review," Pelosi said in a statement.
The Democratic House Speaker said that the original draft of the USMCA, which would update the North American Free Trade Agreement (NAFTA), "still left American workers exposed to losing their jobs to Mexico", Xinhua reported.
"The NAFTA 2.0 draft lacked the concrete, effective enforcement mechanisms needed to ensure that the agreement became more than a list of promises on paper," she said.
House Democrats have negotiated for months with US Trade Representative Robert Lighthizer on changes to the USMCA in four main areas, namely, labor, environment, enforcement, and prescription drug provisions, according to US media.
Richard Trumka, President of the American Federation of Labor and Congress of Industrial Organizations, has warned House Democrats not to expedite approval of the USMCA.
Pelosi's remarks came after US President Donald Trump earlier in the day blamed the House Speaker for not moving the trade deal forward.
"It's sitting on Nancy Pelosi's desk. She's incapable of moving it. It looks like she can't," Trump told reporters.
Pelosi has cast doubt on the possibility of Congress passing the USMCA this year, even if House Democrats and the Trump administration announce a deal within this month.
"I'm not even sure, if we came to an agreement today, that it would be enough time to finish, but it just depends on how much agreement we come to," Pelosi said last week at a news conference.
( With inputs from IANS )