The US Federal Reserve has said that the case for raising interest rates has strengthened further with improving economic conditions, but monetary policymakers decided to wait for more progress before acting.

Just a few days before the bitterly-contested presidential election, the US central bank kept the benchmark interest rate at the same level where it has been since December 2015, a move universally expected by analysts.

However, the Fed, while not explicit on the timing, left the door open to a rate hike soon, possibly in their next meeting in December.

Two central bankers favoured an immediate increase. The Federal Reserve Bank presidents of Kansas City, Esther George, and Cleveland, Loretta Mester, dissented on the vote.

The statement noted continued improvement in the labour market and economic growth, as well as slight increases in inflation, a key focus of the Federal Open Market Committee, the Fed's monetary policy arm.

"The Committee judges that the case for an increase in the federal funds rate has continued to strengthen but decided, for the time being, to wait for some further evidence of continued progress toward its objectives," the FOMC said. 

"The stance of monetary policy remains accommodative, thereby supporting further improvement in labour market conditions and a return to 2% inflation."

Economists widely believe there is a strong chance the Fed finally will raise rates at the December meeting, when it will have the benefit of two more months of inflation and employment data.

"We fully expect this evidence to emerge over the next six weeks, so only a shock - the election of (Donald) Trump, or an external geopolitical or market event - can now prevent a December hike," Ian Shepherdson of Pantheon Macroeconomics said in a research note.

However, Jason Schenker of Prestiges Economics said "there was no signal of an imminent rate hike for December."

Analysts will continue to debate that point, which hinges on a slight language change in the FOMC statement which said policymakers want to see "some" further evidence of continued progress towards its targets, which may or may not be a stronger signal for a rate hike compared to the September statement, when they said only that they need to see "further evidence".