Minutes of the discussions in minutes released Wednesday showed that while Fed officials decided to keep a key rate unchanged at their Jan. 31-Feb. 1 meeting, there was growing concern about inflation if the economy out-performed expectations.

“Several” Fed officials expressed worries that unemployment could fall substantially below the Fed’s 4.8 percent unemployment goal. That could trigger inflation pressures that would require the Fed to boost rates at a faster pace than financial markets currently expect. Unemployment in December was 4.7 percent although it inched back up to 4.8 percent in January.

Most economists had indicated they did not foresee a rate hike until June. But the discussion in the minutes might increase the possibility of a rate increase as soon as March.

Financial markets lost ground immediately after the minutes were released, with investors worried about a potential March rate hike.

The minutes showed that a couple of Fed officials suggested the central bank might need to alter the wording of its policy statement because currently the Fed’s assurances that it planned to raise rates at a “gradual” pace could be “misunderstood as a commitment of only one or two rate hikes per year.”

The minutes were released with the customary three week delay. Fed officials spent time discussing the proposed economic program of President Donald Trump and its possible impact on the economy, although the minutes never mentioned Trump by name.

“Most participants continued to see heightened uncertainty regarding the size, composition and timing of possible changes” to the government tax and spending policies, the minutes said.

While some Fed officials said the central bank should not wait until the outlines of Trump’s program became clearer before raising rates, others urged more caution.

This group argued against “adjusting monetary policy in anticipation of policy proposals that might not be enacted or that, if enacted, might turn out to have different consequences for economic activity and inflation than currently anticipated.”

At the February meeting, the central bank left its key interest rate unchanged while noting that the economy was continuing to advance toward its twin objectives of maximum employment and inflation rising at a moderate annual rate of 2 percent.

The Fed in December boosted its key rate by a modest quarter-point to a new range of 0.5 percent to 0.75 percent. The Fed had waited a full year to raise rates for a second time after its initial rate hike in December 2015.

The Fed noted that even with the two small rate hikes, the Fed’s target for its benchmark federal funds rate — the interest that banks charge each other — remained at a historically low level. It is only slightly higher than the record low near zero where the rate was for seven years as the central bank struggled to jump-start growth in the wake of the worst economic downturn since the 1930s.

After the latest rate hike in December, the Fed issued an updated economic forecast which projected that the central bank expected to raise rates three times in 2017.

Many economists believe the Fed will raise rates between two and three times this year. One complicating factor is the uncertainty over how much of his ambitious economic program President Donald Trump will be able to get through Congress. His stimulus package includes tax cuts for businesses and individiuals, increased infrastructure spending and a roll back of regulations in such areas as banking.

Federal Reserve Chair Janet Yellen, delivering the Fed’s semiannual economic report to Congress, said last week that the economy remains on track to achieve the Fed’s goals and noted the Fed’s December expectation of three rate hikes this year. But she did not signal when the next hike might occur.

“Whether it is March, or May or June … I can’t tell you which meeting it would be,” Yellen told lawmakers.