The market had priced in unchanged interest rates with just over 99 percent certainty.
According to the Bloomberg news agency, Fed decision-makers disagreed about the future interest rate path.
Nine of them predict that the interest rate will be raised this year; six of those believe there will be two increases of 0.25 percentage points each. Nine other members believe that the interest rate will be left unchanged for the rest of the year or will be lowered.
But only 18 of 19 members provided their future projections for the interest rate path. American media speculate that the one member who chose not to do so is Kevin Warsh, who is critical of such projections.
First interest rate meeting for Warsh
The interest rate meeting was Warsh's first as head of the Fed, after Jerome Powell left the post after eight years and amid a media and legal siege from Trump.
The president has repeatedly demanded that the Fed lower interest rates, but Powell stubbornly stuck to the principle of the central bank's independence and autonomy.
This is the fourth time in a row that the Fed has left interest rates unchanged.
Now, the strong labor market and continued high inflation, not least due to increased energy costs, have meant that even fewer people than before believed a reduction was likely.
“Surprising parts”
SEB's US economist Elisabeth Kopelman says there are "some surprising parts" in the Fed's interest rate announcement. Part of this is due to the bank's statement taking a new form compared to previous ones.
"You can see that Kevin Warsh thinks the Fed has talked too much and communicated too much. You can see that he has managed to get the rest of the committee on board with that idea already at the first meeting. It is a very short statement," she says, and continues:
"There was also a lot of discussion about making changes to their guidance and what they're saying about interest rates going forward, and they basically have no guidance at all now. There are a few different opinions about what's happening in the economy."
The median forecast now also indicates a possibility of an increase this year - which was not expected, according to Kopelman. She describes it as surprising that a large portion of members believe that an increase may be needed.
"Then you should keep in mind that this may reflect the situation a week or so ago before this new agreement with Iran began to be presented."
At a press conference after the interest rate announcement, Kevin Warsh also presented ambitious plans to reform the Fed's working methods regarding communication and use of data, which will now be handled by five working groups.
