WASHINGTON — Federal Reserve officials were counting on Congress and the White House to pass additional aid for households and businesses hit by the pandemic as they laid out an optimistic forecast for the economic recovery last month. Now, that outlook is in jeopardy.

In September, the Fed revised its economic forecasts to reflect a much rosier scenario than officials had penciled in earlier in the pandemic recession: Unemployment was seen dipping to 7.6 percent by the end of the year, down from a forecast of 9.3 percent in June. Growth was seen recovering by more, after plummeting early in the year.

But Fed officials “noted that their economic outlook assumed additional fiscal support and that if future fiscal support was significantly smaller or arrived significantly later than they expected, the pace of the recovery could be slower than anticipated,” according to minutes from the Sept. 15-16 meeting, which were released on Wednesday.

The Fed’s staff, likewise, “assumed the enactment of some additional fiscal policy support this year” without which “the pace of the economic recovery would likely be slower.”

Now, the bet that more public money is right around the corner is crumbling. President Trump pulled the plug on stimulus negotiations on Tuesday, before suggesting later in the evening that he would approve stand-alone bills.

Risks to the economic outlook that the Fed fretted over in September seem to be growing more prominent by the day.

Last month, Fed officials said they “remained concerned about the possibility of additional virus outbreaks,” noting they “could result in increases in bankruptcies and defaults, put stress on the financial system, and lead to disruptions in the flow of credit to households and businesses.”

In the weeks since, cases of the coronavirus have begun to rise again. Over the past week, there have been an average of about 44,000 cases per day, an increase of 6 percent from the average two weeks earlier, according to The New York Times’s tracker.

While that is only a slow uptick, it underlines the uncertain territory the U.S. economy is entering as it begins the final quarter of 2020. Millions of people remain out of work, many businesses remain all or partly closed, and cold weather could mean both a decline in outdoor dining and a further increase in coronavirus cases at a time when the economy remains much weaker than it was before the pandemic took hold in March.

Despite improvements in the unemployment rate, “we are nowhere near where we want to be,” John C. Williams, the president of the Federal Reserve Bank of New York, said in remarks delivered on Wednesday. “This is not a standard recession, and the economic future is inextricably tied to the spread of the virus.”

Government lifelines, including a $600 expansion of unemployment benefits, have run dry at a moment when many economists say more help is needed.

“If we don’t support people who have lost their jobs, then they can’t pay their bills, and then it ripples through the economy, and the downturn is much worse than it needs to be,” Neel Kashkari, the president of the Federal Reserve Bank of Minneapolis, said on CNBC on Wednesday.

It is unclear how quickly fading support for out-of-work Americans will inflict harm on the broader economy. Some Fed officials said in September that the savings cushion households have built up since the pandemic took hold could help sustain spending. But others said if that buffer reflected reduced spending by high-income consumers, rather than distressed households, “it was unlikely to provide much momentum to future consumption.”

The Fed has taken far-reaching actions itself to support the economy, cutting rates to near zero, buying huge quantities of bonds and rolling out never-before-tried emergency lending programs for companies and state governments.

In its most recent policy statement, the Federal Open Market Committee said it expected to hold rates steady near rock bottom — where they have been since March — until the job market reached what it saw as full employment “and inflation has risen to 2 percent and is on track to moderately exceed 2 percent for some time.”

That significant update reinforced a pledge the Fed made in August to tolerate higher price gains to offset periods of weak inflation, and it underscored that officials will be patient as they try to help the economy through the months and years ahead.

But the minutes show that officials left wiggle room around their promise. The committee debated the new language thoroughly, the minutes suggested, and even those who supported it said the guidance could change “if risks emerged that could impede the attainment of its economic objectives.”

Several officials worried that promising to keep rates low until the Fed had achieved its goals “could limit the committee’s flexibility for years.”

Fed officials signaled at the September meeting that they would continue buying about $120 billion in government and government-backed bonds each month, a policy meant to keep markets functioning normally while making credit a little bit cheaper. Some officials said that “in future meetings it would be appropriate to further assess and communicate” how that bond-buying supports the Fed’s economic goals.

While Fed officials regularly pledge to use all of their tools to support the recovery, they also often say that they alone cannot determine how the economy shapes up.

The trajectory for bankruptcies and hiring will depend “on the degree to which additional fiscal support may be forthcoming to help households, firms and, importantly, state and local governments navigate through these difficult times,” Charles Evans, the president of the Federal Reserve Bank of Chicago, said in a speech on Wednesday.

He pointed out, in a footnote, that he had “spoken extensively about the need for additional fiscal policy support.”