WASHINGTON — Federal Reserve Chair Jerome Powell took a sharp and unexpected turn Tuesday toward tightening credit for consumers and businesses in the face of mounting concerns about high inflation.

Powell signaled that the Fed will likely act more quickly to phase out its ultra-low-interest rate policies even as the emergence of the new omicron variant of COVID-19 has raised fresh doubts about the future of the economy and the direction of inflation.

The Fed chair told the Senate Banking Committee that the central bank’s policymakers will discuss at their next meeting in mid-December whether to accelerate the reduction of their monthly bond purchases, which have been intended to lower long-term borrowing costs. The Fed just announced those reductions in early November at a pace that would end the bond buying in June. But on Tuesday, Powell signaled that the Fed is inclined to end those purchases several months before then.

Doing so would put the Fed on a path to begin raising its key short-term interest rate as early as the first half of next year. That rate has been pegged at nearly zero since last March, when the coronavirus sent the economy into a deep recession. A higher Fed rate would, in turn, raise borrowing costs for mortgages, credit cards and some business loans.

Very low interest rates, nurtured by the Fed, have been a key factor in driving share prices to all-time highs since the pandemic struck.

“He was decidedly more hawkish in tone than I expected and, I think, than the financial markets expected,” said Kathy Bostjancic, chief U.S. financial economist at Oxford Economics.

Fed policymakers have come under pressure from a sharp jump in inflation, with consumer prices having soared 6.2% in October from a year earlier, the highest such inflation rate in 31 years. In response, some Fed officials in recent weeks had already started to push for a faster tapering of the central bank’s bond purchases.

Yet the sudden emergence of the omicron variant had led some Fed-watchers to speculate that the central bank would avoid any major policy shifts until a clearer picture of the variant and its likely impact on the economy emerged.

“The economy is very strong, and inflationary pressures are high,” Powell said. “It is therefore appropriate, in my view, to consider wrapping up the taper of our asset purchases … perhaps a few months sooner.”

“This is a very abrupt pivot from the Fed,” said Krishna Guha, an analyst at the investment bank Evercore ISI. “The eight-month taper plan was only announced four weeks ago.”

Under fire from some Senate Republicans about worsening inflation, Powell suggested that price increases will likely slow next year as supply bottlenecks ease. But he also acknowledged that price increases have been spreading to broader categories of products and services, and as a result “the risk of higher inflation has increased.”

For months, Powell and other Fed officials had described inflation as “transitory,” which did not necessarily mean they thought it would disappear soon but that it wouldn’t keep spiraling higher. That outlook has so far proved too optimistic, and Powell said it is “probably a good time to retire that word and try to explain more clearly what we mean.”

The Fed chair said he thought the central bank’s policymakers will know more about the potential economic impact of the omicron variant in time for their next meeting in mid-December.

Regardless of the eventual consequences, the omicron variant seems sure to make Powell’s job more complicated next year. If omicron leads to another wave of factory and port shutdowns in the United States and overseas, supply chain bottlenecks could worsen and raise prices even more.

At the same time, omicron could renew fears among many workers about becoming infected on the job, leading to more resignations when quits are already at a record high or discouraging some of those out of work from taking a new job. That could weaken the job market and the economy. Under such a scenario, the Fed’s dual mandates of stable prices and maximum employment could come into conflict.

In a significant shift, Powell appeared to make inflation-fighting a more urgent priority than job growth by noting that higher prices themselves threaten the economic recovery. And a long period of growth, he said, is needed to regain the “great labor market” that existed before the pandemic.

“We’re going to need a long expansion,” the Fed chair said. “To get that, we’re going to need price stability, and in a sense, the risk of persistent high inflation is also a major risk to getting back to such a labor market.”

Rising inflation has put the Fed in a delicate spot, because the economy remains about 4 million jobs short of pre-pandemic levels, and many Democrats in Congress will want to see rates stay near zero until most of those jobs have been recovered.

“The Fed cannot pump the brakes on our economic recovery too soon, before workers get a chance to fully rebound,” said Sen. Sherrod Brown, the Ohio Democrat who chairs the Banking Committee. “And I mean all workers,” he added, noting that the Black unemployment rate remains twice that of white Americans.

By contrast, Sen. Pat Toomey from Pennsylvania, the senior Republican on the committee, suggested that the economy largely recovered roughly a year ago. As a result, emergency measures, such as the Fed’s bond purchases, haven’t been needed since then, he said.

Treasury Secretary Janet Yellen, who also testified before the Senate Banking panel Tuesday, urged Congress to raise the nation’s borrowing limit. Yellen has previously warned that without an increase in the debt ceiling, the government could default on its debt obligations for the first time soon after Dec. 15.

“I cannot overstate how critical it is that Congress address this issue,” she said. “America must pay its bills on time and in full. If we do not, we will eviscerate our current recovery.”

Congress, which is expected to address the borrowing limit, also faces a Friday deadline to provide enough funding to keep the federal government open.

Yellen also said that for now, the economic recovery “remains strong,” but she urged that Americans get vaccinated or receive booster shots to guard against the omicron variant.