U.S. House Speaker Nancy Pelosi (D-CA) speaks at her weekly news conference on Capitol Hill in Washington, U.S., May 2, 2019.

House Speaker Nancy Pelosi will meet with President Donald Trump's top trade negotiator Wednesday during a key stretch for the White House's trade policy, a senior Democratic aide said.

Pelosi, joined by House Majority Leader Steny Hoyer, D-Md., House Majority Whip James Clyburn, D-S.C. and House Ways and Means Committee Chairman Richard Neal, D-Mass., will huddle with U.S. Trade Representative Robert Lighthizer in the afternoon. They will primarily address the president's updates to the North American Free Trade Agreement but will likely discuss the widening trade war with China as well, according to the aide.

The meeting comes as Pelosi and top House Democrats show reservations about approving an updated version of the North American Free Trade Agreement, which Trump has dubbed the United States Mexico Canada Agreement. They have expressed concerns about whether the deal has sufficient environmental and labor protections. They have also worried about whether certain provisions could increase drug costs.

Pelosi has shown no rush to bring the agreement to the House floor for ratification. When asked last week about how far away an approval vote is, she said "we're as far away as getting an enforcement agreement."

The meeting also follows escalations in the trade war between the U.S. and China. After the Trump administration hiked tariffs on $200 billion in Chinese goods last week, Beijing retaliated by raising duties on $60 billion in American products. The move raised fresh concerns about damage to American businesses — particularly farmers — and higher costs for consumers.

Pelosi has agreed with the broader aims of Trump's push to crack down on what he calls Chinese trade abuses. Last week, she said "the president is correct in asserting what we have to do with China." But she contended his tactics are "empowering [China] to hurt our people."

The House speaker has said she has a good relationship with Lighthizer, who led the administration's North American negotiations and heads its talks with China. The U.S. trade representative is seen as more aggressive on China trade policy than Treasury Secretary Steven Mnuchin.

Read more: There is 'no chance' Trump will back down in the China trade war, Steve Bannon says

Former Trump advisor Steve Bannon — who helped to inspire the president's 2016 campaign pledges to target Beijing — told CNBC he thinks the president and Lighthizer are on the same page.

"There's no gap between Lighthizer and President Trump," Bannon said Wednesday. "Lighthizer is the guy that does the execution."

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