Congressional leaders are eyeing a short-term deal to keep the government funded past a Sept. 30 deadline, working to buy themselves time to resolve major spending disputes without shutting down the government.

Top Republicans and Democrats in the Senate and House have conceded that a stopgap bill will be needed to keep government funds flowing while they try to reach a long-term compromise that can clear Congress and be signed by President Trump. The government is currently being funded by such an interim measure that was enacted in March.

But with Republicans pushing for deep cuts and Democrats resisting, a broad spending agreement will be exceedingly difficult. And even a short-term measure is likely to be challenging, with the two parties divided over key details. Such a package would also pose a political challenge for Democrats, who weathered a backlash from their voters in March when they allowed the current stopgap spending bill to move forward.

“We don’t want a shutdown,” said Senator Chuck Schumer of New York, the Democratic minority leader. “We want bipartisan negotiations and a bipartisan bill. If Republicans want to keep the government open, they’ve got to work with us.”

Back in March, Democrats agonized for days over whether to supply the votes needed to allow the G.O.P.-written temporary spending measure to move ahead. Mr. Schumer and nine other members of his caucus ultimately voted to let it advance, arguing that a shutdown would only empower Mr. Trump to tighten his grip on federal agencies and to unilaterally decide what money to spend.

Democrats have said they would find it extremely difficult to back future funding measures without some kind of assurance that Republicans would not continue to allow the Trump administration to cancel spending after Congress approves it. In order to clear a Senate filibuster, government spending deals have historically been bipartisan products.