Senate Republicans may face roadblocks in their effort to pass a longterm highway bill by the end of the month.

Senate Democratic leaders said they will vote Tuesday against a bipartisan, long-term highway funding measure because they need more time to review the legislation.

And House Republican leaders said they prefer their own short-term patch.

Minority Leader Harry Reid, D-Nev., said he has not seen the details of the measure, brokered between Senate Majority Leader Mitch McConnell, R-Ky., and the top Democrat on the Environment and Public Works Committee, Sen. Barbara Boxer, D-Calif.

The deal, according to McConnell, would authorize surface transportation projects for the next six years, although the proposal is funded for just three years.

McConnell has scheduled a 4 p.m. procedural vote that would allow the Senate to begin debating the proposal.

But Democrats could block it, Reid said.

"We are not going to vote on a bill we haven't seen," Reid said. "We'll vote on it. But not favorably."

Reid said he did not know whether Democrats would be unified enough to block moving forward on the legislation. All of the Democratic leaders pledged to vote against it.

Republicans, meanwhile, are touting the bill as a major achievement in highway funding, which for more than a decade has been authorized in short-term patches.

The House passed another short-term patch earlier this month that would keep highway projects funded until December.

House Republican leaders say they prefer their approach, which would give Congress more time to work on a long-term deal that could involve international tax reform.

"I think the Senate should take up our short term bill and pass that," House Majority Leader Kevin McCarthy, R-Calif., told reporters Tuesday.

But McConnell wants to achieve a long-term deal, partly because he wants to demonstrate the Senate can pass bipartisan legislation under his leadership after years of gridlock while Democrats were in charge of the Senate.

"We are anxious to move the bill forward, in the hopes that the House will consider it," McConnell said Tuesday.

He added that he is hoping the bill "will be attractive to the House," which is also eager to end the decade-long stretch of short-term highway funding measures, which Republican leaders said added 30 percent to the cost of road and bridge improvements because it hurts long-term planning.

"Enough is enough," McConnell said.