President Biden's calls for the Senate to pass aggressive background check bills and a ban on assault weapons face an uphill battle with a key Democrat already voicing disapproval.

Sen. Joe Manchin, a moderate Democrat from West Virginia, said Tuesday he can't support the pair of Biden-backed background check bills that the House already passed. 

"No, not at all," Manchin told reporters Tuesday at the Capitol when asked if he could vote in favor of the House legislation. 

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Passing gun control legislation has been notoriously tough in the Senate, where it takes 60 votes to get things done as long as the legislative filibuster is in place. While progressives are putting tremendous pressure on Democrats to abolish the filibuster to pass big reforms with a simple majority, it was clear Tuesday that Biden and the 50 members of the Democratic caucus were not unified on how best to proceed on guns. 

Senator Joe Manchin, a Democrat from West Virginia, speaks to members of the media while departing a bipartisan Senate luncheon in Dirksen Senate Office Building in Washington, D.C., U.S., on Wednesday, March 3, 2021.  Photographer: Stefani Reynolds/Bloomberg via Getty Images

Biden Tuesday called on the Senate to pass an assault weapons ban and two expanded gun background check bills the House passed earlier this month. He stressed the urgency to act after another mass shooting in America, this time in Boulder, Colo. where 10 people died.

"This is not and should not be a partisan issue," Biden said. "This is an American issue that will save lives, American lives. And we have to act."

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The House bills expand federal gun background checks on all firearms sales and extend the background check review period from three days to a minimum of 10 business days.

Manchin, instead, wants to see a revival of his 2013 compromise legislation with Sen. Pat Toomey, R-Penn., that focused on closing commercial sale gun loopholes but didn't require background checks to apply to family and friends giving or selling guns to each other. 

"I come from a gun culture. And I'm a law-abiding gun owner [who] would do the right thing," Manchin said in explaining his more "reasonable" proposal. "You have to assume we will do the right thing, give me a chance to do [it]. So I'm still basically where Pat Toomey and I have been."

A memorial has been erected to honor the 10 victims of Monday's shooting on Table Mesa in Boulder, Colo. The victims include Boulder Police Officer Eric Talley

Senate Majority Leader Chuck Schumer, D-N.Y., said Tuesday he hasn’t spoken with the White House about an assault weapons ban. Such a ban is not part of the pair of House bills that passed earlier this month.

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Instead, Schumer said his focus is bringing a universal background check bill to the floor, but he acknowledged he's still working with senators on the specifics.

"We will figure out the best path forward," Schumer said Tuesday.

Meanwhile, Republicans were quick to point out the divisions within the Democratic Party on guns. 

"I share Joe Manchin's opposition to the version that passed in the House," Senate GOP Leader Mitch McConnell, R-Ky., said Tuesday.

Despite the coronavirus lockdowns that have shuttered schools, nightclubs and concert venues, gun deaths in the United States have shot up significantly during the pandemic, according to data tracked by the Gun Violence Archive.

In 2020, there were 19,380 non-suicide gun deaths in America, up from 15,208 in 2019.

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Mass shootings of four or more people also jumped from 417 to 611 last year, fueled by drive-by shootings, according to the Gun Violence Archive. 

"2020 was a surprisingly more active year," Mark Bryant, executive director of the Gun Violence Archive, told Fox News. "We anticipated people being in would provide less opportunities for shooting, and the opposite occurred."

Fox News' Morgan Phillips contributed to this report.