By Andrew Duehren 

WASHINGTON -- Members of a bipartisan group of senators said they had reached an agreement on an infrastructure proposal that would be fully paid for without tax increases, pitching the plan to other lawmakers and the White House as they try to craft compromise legislation on the issue.

While the group of 10 senators didn't reveal details of the plan in its statement, people familiar with the plan said it called for $579 billion above expected future federal spending on infrastructure. The overall plan would spend $974 billion over five years and $1.2 trillion if it continued over eight years, according to some of the people.

The initial agreement comes days after President Biden called off a separate set of negotiations with Senate Republicans over an infrastructure plan, instead pivoting his focus to the talks among the group of five Republicans and five Democrats.

To move forward in Congress, the plan would need the buy-in from a broader group of Republicans and Democrats, as well as the White House. In recent days, some Democrats have indicated they are skeptical that the bipartisan talks will result in a large enough package.

"We are discussing our approach with our respective colleagues, and the White House, and remain optimistic that this can lay the groundwork to garner broad support from both parties and meet America's infrastructure needs," said the group, which includes Sens. Kyrsten Sinema (D., Ariz.), Rob Portman (R., Ohio) and Joe Manchin (D., W.Va.).

The White House didn't immediately comment on the announcement by the senators.

Republicans said the infrastructure investments wouldn't be paid for by tax increases, but lawmakers have been tight-lipped about how they fund the package, expected to be the most contentious part of the negotiations. Sen. Mitt Romney (R., Utah), another member of the group, said earlier Thursday that the group was looking at indexing the gas tax to inflation. The federal gasoline tax hasn't been increased since 1993.

The new proposal is also expected to be paid for in part by repurposing funds from previous Covid-aid packages, said Sen. Shelley Moore Capito (R., W.Va.), who led the last round of negotiations with Mr. Biden and has talked with members of the bipartisan group.

Mr. Biden last week indicated he would be open to using about $75 billion of Covid aid passed during the Trump administration, but administration officials said he wouldn't siphon any funds from the $1.9 trillion Covid-19 relief package passed earlier this year.

Write to Andrew Duehren at andrew.duehren@wsj.com

(END) Dow Jones Newswires

June 10, 2021 18:18 ET (22:18 GMT)