By Kanishka Singh

WASHINGTON, Oct 28 (Reuters) - Democratic leaders in the U.S. House of Representatives said they would not vote on Thursday on a bipartisan infrastructure plan as their leaders had suggested after progressives balked.

Speaker Nancy Pelosi said late on Thursday that the House will postpone the vote on the infrastructure bill pending in the U.S. Congress, but added that most members of the House had expressed a commitment to support the legislation.

White House Press Secretary Jen Psaki said the Biden administration was confident that the infrastructure bill and a more complicated spending measure for social spending and tackling climate change would soon be passed by Congress.

U.S. President Joe Biden earlier on Thursday presented a $1.75 trillion plan for climate measures, preschool and other social initiatives that he said unified Democrats, but some members of his party quickly rebuffed it.

Dozens of progressive Democrats in the House opposed a quick vote on a $1 trillion infrastructure bill until agreement is reached on a larger social spending bill, their leader said on Thursday.

Pelosi earlier in the day had urged Democrats to vote Thursday to pass the infrastructure bill, giving Biden a legislative victory.

But Representative Pramila Jayapal, the chair of the Congressional Progressive Caucus, said the group was holding out for more of Biden's agenda to be ready to pass.

Progressives had long said they would not vote for the infrastructure bill, which passed the Senate with bipartisan support in August, until the details of the larger bill - once targeted at $3.5 trillion - were worked out.

Democrats said the vote on the temporary transportation funding bill would be the chamber's last vote of the week. (Reporting by Kanishka Singh and Tim Ahmann; Editing by Mohammad Zargham and Cynthia Osterman)

(Adds statement from White House, Pelosi late on Thursday)