WASHINGTON — Federal Reserve officials are struggling to make sense of a new economic reality in which low inflation and low unemployment are persisting side by side.

At the Fed’s most recent meeting, in late July, most officials said they expected the phenomenon to fade away by next year as low unemployment finally starts to drive up inflation.

But a growing number of officials see the pattern as proof that the Fed needs to adjust its assumptions, according to an account of the meeting that the Fed published on Wednesday.

At the July meeting, the Fed left its benchmark rate in a range of 1 percent to 1.25 percent. It also said it planned to start reducing its asset holdings “relatively soon.” The minutes said some Fed officials were ready to announce a starting date for the reductions, but most favored just a little more patience. Analysts expect an announcement after the Fed’s next meeting, Sept. 19 and 20.