The Fed has already eased rates three times since September in a bid to inject confidence into jittery markets. But analysts cautioned that central bankers may now feel constrained against further easing: inflation is growing, particularly as oil hovers near $100 a barrel. Lower interest rates, over time, can generate the seeds of inflation, and could make an already weak dollar worth less against foreign currencies.

“The Fed is trying to juggle a two-sided sword,” said Ryan Larson, senior equity trader at Voyageur Asset Management. “They’re trying to fight inflation moving higher and they’re trying to fight a slowdown in growth.”

In an effort to encourage lending, the Fed has been pumping cash through the banking system by auctioning off loans at discounted rates. On Friday, it said it would expand a pair of auctions scheduled for this month, offering $30 billion.

Some economists said the markets and other analysts were making too much of a lone jobs report that could yet be revised.

“The stock and bond markets are going into panic mode,” said Michael Darda, chief economist at MKM Partners, a research and trading firm in Greenwich, Conn. “We’re going to have a slowdown, but I don’t think we’re going to have a recession.”

While filings for jobless benefits have been rising in recent weeks, the pace has not been swift enough to justify such a sharp jump in the unemployment rate, Mr. Darda added.

For months, the economy had managed to grow vigorously despite worrying developments, from the unraveling of the housing industry to turmoil in the credit markets. Through it all, economists marveled at the resilience of the labor market, suggesting that as long as the economy kept creating jobs by the tens of thousands each month, Americans would keep spending and growth would carry on.