WASHINGTON — Furious opposition from both the House Democrats’ most ardent liberals and their fiscal hawks forced Democratic leaders on Tuesday to delay voting on a two-year budget measure that would increase military and domestic spending, an embarrassing send-off as the new majority prepared to leave for a three-day retreat.

The decision to indefinitely postpone the vote underscored the Democrats’ lack of unity almost 100 days into their majority and the challenge facing Speaker Nancy Pelosi and her leadership team as they try to bridge an ideological gap between upstart progressives flexing their muscles and more moderate members clinging to their Republican-leaning seats.

“This is not an outcome,” Ms. Pelosi told reporters on Tuesday. “This is a process.”

Asked if a spending deal was possible despite the party’s factions, Ms. Pelosi said, “Of course.”

The bill — championed by Representatives John Yarmuth of Kentucky, the chairman of the House Budget Committee, and Nita M. Lowey of New York, the chairwoman of the House Appropriations Committee — would set higher military and domestic spending levels than the hard caps fixed in the Budget Control Act of 2011. It had been presented last week as a substitute to a broader budget blueprint that would have outlined policy priorities in health care, taxation, defense and other areas, as well as new spending limits.