In this Sept. 24, 2021, file photo House Speaker Nancy Pelosi, D-Calif., joined at left by Rep. Brenda Lawrence, D-Mich., holds a rally in support of President Joe Biden's "Build Back Better" for women agenda, at the Capitol in Washington. Credit: J. Scott Applewhite / AP

WASHINGTON — House Speaker Nancy Pelosi pledged to pass a $550 billion infrastructure bill this week and signaled that the headline amount on a bigger package of spending and tax measures will be lowered from $3.5 trillion.

In a nod to moderate Democrats eager to enact the roads-and-bridges bill, Pelosi said in a letter to caucus members that she’ll open debate on the Senate-passed measure Monday and put it to a vote on Thursday.

“Well, let me just say we’re going to pass the bill this week,” she said on ABC’s “This Week” earlier Sunday.

Divisions between progressive and moderate Democratic factions have set up a showdown over President Joe Biden’s economic agenda, with Pelosi facing competing demands to keep both bills on track to Biden’s desk. Even so, two lawmakers on opposite sides of the divide sought to project a conciliatory tone on Sunday.

With high stakes in play for his presidency, Biden said he’s “optimistic about this week.” A White House official said the president and his team held talks with lawmakers over the weekend about the path forward on both bills and that conversations would continue on Monday.

“It’s going to take the better part of the week, I think,” Biden told reporters at the White House on Sunday after returning from the presidential retreat at Camp David. While setting a date for the infrastructure vote, Pelosi said House Democrats are working with the Senate and the White House on changes to the larger bill.

Progressives, whose votes are likely to be crucial, are insisting on progress first on the bigger bill, which includes spending on everything from child care to climate protection. Moderates such as West Virginia Senator Joe Manchin have said the price tag is too high.

More negotiations on the package lie ahead, “especially in terms of addressing the climate crisis,” and it “seems self-evident” that the headline number is going to be smaller than $3.5 trillion, Pelosi said on ABC.

Congressional Democrats are using a fast-track budget process known as reconciliation to push the bigger of the two plans through the Senate, bypassing Republicans. The House Budget Committee advanced a draft version of the bill on Saturday, a required procedural step before it can be brought to a floor vote.

Pramila Jayapal, the Washington State representative who chairs the House Progressive Caucus, said on CNN’s “State of the Union” that Pelosi didn’t have the votes to pass the infrastructure bill on Monday.

Representative Josh Gottheimer, a key moderate, said the bottom line was that “we vote on it early this week.” He also expressed support for the bigger bill prioritized by progressives.

“And we also have to get reconciliation done,” the New Jersey Democrat said on CNN. “And that’s also going to get done.”

Jayapal said she and Gottheimer have been talking “a lot over the last week” and “I believe they want to find a way through this.”

Also on Congress’s agenda is avoiding a federal government shutdown looming at the end of the month and a potential default on U.S. government obligations in the weeks ahead.

The Senate is expected to vote this week to take up a House-passed stopgap funding bill that includes a suspension of the debt ceiling, though Republican opposition is likely to block its consideration.

Pelosi said she’s still hopeful for enough Republicans to find “some level of responsibility” and join in raising the debt limit. “We want this to be bipartisan,” she said.

At the same time, she said: “We need to make sure we keep government open — and we will.”

Pat Toomey, Republican senator of Pennsylvania, said Republicans won’t vote to raise the debt ceiling, and Democrats will have to do so “all by themselves.” He spoke on CNN’s “State of the Union.”

Story by Yueqi Yang and Tony Czuczka.