Senate Democrats hope to complicate the future of a Republican-led bill that would shield gun manufacturers (search) and distributors from lawsuits arising from crimes in which guns were used.

The GOP-controlled Senate plans to take up the legislation Wednesday, with Republicans saying they have enough votes to pass it in an early morning vote. But Democrats plan to force votes on at least two other gun issues they want to attach to it, including an amendment to renew the assault weapons ban and another to require background checks for all purchasers at gun shows.

"The bill will provide an opportunity to vote on these issues," said Sen. Jack Reed, D-R.I., who opposes the bill but supports the Democratic amendments. "What's going to happen after that, I don't know."

Republicans, along with Senate Democrats, have been pushing for the gun immunity legislation (search) for some time. Gun advocates say firearm makers shouldn't be forced to spend millions of dollars fighting off lawsuits designed to win large rewards and bankrupt them for making legal products.

Gun rights groups plan to urge majority Republicans to defeat the proposed amendments. The GOP-controlled House already has said it does not plan to approve the extension of the assault weapons ban.

The White House has urged the Senate to pass the legislation without amendments.

"The administration urges the Senate to pass a clean bill, in order to ensure enactment of the legislation this year," the White House said in a statement. "Any amendment that would delay enactment of the bill beyond this year is unacceptable."

Democrats including Senate Minority Leader Tom Daschle of South Dakota agreed to back the legislation after gun supporters accepted a specification that firearms manufacturers and distributors would not be immune to lawsuits involving defective products or illegal sales.

Getting the 1994 assault weapons prohibition (search) renewed has been a Democratic priority this year. They picked up support Tuesday from GOP Sens. John Warner of Virginia, Mike DeWine of Ohio and Lincoln Chafee of Rhode Island.

"Although I voted against the ban a decade ago, over the past 10 years it has reduced crime dramatically and has made our streets safer," Warner said. "The legislation also has protected the rights of gun owners better than many of us predicted."

The three GOP senators' support does not guarantee the amendment's approval in the Senate, but "this gives the effort to renew the assault weapons ban new momentum," said Sen. Dianne Feinstein, D-Calif., sponsor of the original assault weapons ban.