US President Joe Biden on Friday urged his fellow Democrats in Congress to overcome divisions that threaten his agenda and pass legislation to bolster safety-net programmes, fight climate change and rebuild the nation's roads and bridges.
Fresh disagreements developed among Democrats over the size of a $3.5 trillion companion bill that would fund health, education and climate measures.
The president acknowledged in a closed-door meeting that Democrats currently did not have enough votes to pass the two spending bills that have divided moderates and progressives, members of Congress said.
"It doesn't matter whether it's in six minutes, six days or in six weeks. We're going to get it done," Mr Biden told reporters after the meeting.
Members of the party's progressive wing have vowed to block the $1tn infrastructure bill until they can be sure that moderates will not derail the bigger social spending and climate change bill. Moderates say that bill is too expensive.
US presidents rarely visit Capitol Hill, preferring to summon politicians to the White House for discussions.
Members of Congress said Mr Biden told them the social spending bill should cost about $2tn — a significant drop from his initial $3.5tn proposal, and closer to the $1.5tn that Joe Manchin, a key moderate senator, said he would support.
Democratic leaders in the House did not appear to have a clear plan for resolving the impasse.
"We are working on trying to get to a place where everybody is comfortable," House Democrat Steny Hoyer told reporters before Mr Biden's visit.
Also before the president's visit, House of Representatives Speaker Nancy Pelosi vowed to hold a vote on a $1tn infrastructure bill on Friday.
"We'll vote today," Ms Pelosi told reporters.
A similar promise by the speaker on Thursday was not fulfilled and it is unclear if the timeline will change after Mr Biden's statement allowing for flexibility on timing.
The Senate, in a bipartisan August vote, passed the $1tn bill, which includes funds for roads, bridges and other infrastructure. Moderates had pushed for a vote this week while progressives insisted they would not approve the bill without agreement on a companion bill that Senate Democrats intend to pass without Republican votes.
Republican senators who voted in favour of the bipartisan infrastructure deal this summer expressed frustration at the lower chamber's struggles to pass it.
"It is a big missed opportunity," Republican Rob Portman said. "This is good for the country. It is exactly what we ought to be doing around here."
Faced with increasingly stiff odds of passing their $3.5tn social spending proposal, Mr Biden and his aides are trying to find out what narrower proposal could unite an ideologically fractured Democratic caucus, people familiar with the matter said.
Members of the party's left flank have said they will not vote for the infrastructure bill unless they feel certain their priorities will be reflected in the social spending bill.
Ilhan Omar, a leading House progressive, told reporters on Thursday: "Nothing has changed with our caucus members. We don't have the votes to pass infrastructure."
More than half of the 96-member Congressional Progressive Caucus held firm in their threats not to back the infrastructure package without first passing the social spending proposal.
Moderate Joe Manchin has proposed a spending package of about $1.5tn. Another Democratic moderate, Kyrsten Sinema, declined to say whether she agreed with Mr Manchin's proposal, but in a statement on Thursday, confirmed her opposition to the current $3.5tn price tag.
Both Mr Manchin and Ms Sinema had met with Mr Biden multiple times this week to piece together a framework on the deal.
Ms Sinema has met with Mr Biden multiple times to discuss the bill. She was home in Arizona on Friday but remained in touch with the White House, a spokesman said.
Reuters contributed to this report