President Joe Biden threw his support behind an infrastructure proposal negotiated by a bipartisan group of senators, boosting momentum for the deal even as congressional leadership also presses forward with a larger bill addressing the more ambitious aspects of the president’s agenda.

“We have a deal,” Mr. Biden told reporters outside the White House after a meeting with the 11 senators of both parties who had negotiated the package. “We made serious compromises on both ends.”▶ Watch Video: Breaking down President Biden’s domestic agenda, voting rights and infrastructure

The deal is a victory for Mr. Biden, who spent nearly 40 years in the Senate before becoming vice president and has positioned himself as a dealmaker who is able to work with both sides of the aisle. However, the proposal may have a rocky path to passage, as several progressive Democrats in the House and the Senate have expressed displeasure about the exclusion of provisions related to climate change, child care, health care and education.

The proposal would cost roughly $1 trillion, with $579 billion in new spending. The group of 21 senators initially announced their agreement on a proposal last week, but still differed on how the measure would be funded. They then declared on Wednesday evening that they had reached an agreement on a “framework,” including pay-fors, which is what the team presented to Mr. Biden on Thursday.

“We didn’t get everything we wanted, but we came up with a good compromise that’s going to help the American people,” GOP Senator Rob Portman told reporters after the meeting with Mr. Biden.

Democratic Senator Kyrsten Sinema said the deal counters the notion that “bipartisanship is dead in Washington,” but instead “shows that when a group of people who are committed with shared values to solving the problems and challenges our country faces, we can use bipartisanship to solve these challenges.”

The details of the bill are still unclear, including the exact breakdown of what will be included and how it will be funded, although Portman said it would not include any new taxes. It will be narrowly focused on “traditional” infrastructure priorities such as roads, bridges, improving railways and expanding broadband. GOP Senator Bill Cassidy said there would be $47 billion for resiliency “that will be essential as we address our changing environment.” There is also expected some spending on electric vehicle charging stations, a priority for Mr. Biden.

Although 21 senators have signed onto this bipartisan measure, it will need the support of 60 senators to advance to a full vote on the Senate floor. Several progressive Democratic senators have warned that they will not support the bipartisan bill unless they get a firm commitment that issues such as climate change and “human” infrastructure, including child care and health care, will be addressed in a larger reconciliation bill.

“Way too small. Paltry. Pathetic. It has to be combined with a second much more robust, adequate package to be deserving a vote,” Democratic Senator Richard Blumenthal said.

Senator Elizabeth Warren told reporters “we are not leaving childcare behind, we are not leaving home health care behind, we are not leaving the green energy changes that we need to save our planet behind, and we are not going to make America’s middle class families pay for this package.”

“We need assurances from all 50 people in our caucus that we have a deal and it is not just a deal on numbers. It is a deal on what gets covered,” Warren said.

This is a breaking story. It will be updated.