“An emergency cut by the Fed prior to the meeting is possible — it will depend on the extent of market dysfunction,” they wrote.

The stock market trimmed its losses after Mr. Powell’s statement was released at 2:30 p.m., but remained in significantly negative territory.

“The statement is a step in the right direction, but it stops short of what is needed, which I think is a statement that says that the Fed can act preemptively to support the economy,” said Roberto Perli, an economist at Cornerstone Macro. “It’s missing a sense of timing.”

Mr. Powell’s colleagues have expressed concern about the coronavirus, but several have also signaled that they were not ready to lower interest rates. James Bullard, the president of the Federal Reserve Bank of St. Louis, said during a speech in Florida earlier Friday that “we could cut rates if we got a global pandemic that actually develops with health effects that seem to be approaching the same level as seasonal influenza, but that doesn’t look like the baseline as of today.”

The statement by the Fed chair underlines that the most important member of the 17-person Federal Open Market Committee is closely focused on an unfolding public health concern.

Loretta J. Mester, the president of the Federal Reserve Bank of Cleveland and a monetary policy voter this year, said in an interview on Thursday that the Fed should keep its options open. Ms. Mester, who is generally cautious about such moves, initially opposed the Fed’s decision last year to lower borrowing costs three times.

“We always have to come in with open minds about what’s going on with the economy, and every day we’re getting new information, especially with something that’s fast-moving, like this,” Ms. Mester said when asked whether a cut next month was possible.