Friday's jobs report should reassure Federal Reserve officials the economy is improving as they have predicted and it could intensify their debate about when to start raising short-term interest rates.

Fed officials have encouraged a view in financial markets that they won't start raising rates from near zero until mid-2015. But a swift decline in the jobless rate in recent months—while welcome for the economy—means slack in the labor market might be diminishing a bit faster than officials expected, a possible source of higher inflation in the future and of tension inside the Fed as officials consider how long to wait on raising rates.

"There is a pretty high bar for them changing the mid-2015 indication," said Alan Levenson, chief economist at T. Rowe Price Associates . "I have thought for quite some time that they ought to be getting off of zero."

The surprise in Friday's report for the Fed was the stability of the U.S. unemployment rate at 6.3% in May and April. A number of officials expected to see the jobless rate rise a bit in May after such a large drop in April from 6.7% in March.

The next touch point in Fed officials' debate about labor-market slack will be the projections they release in mid-June for the unemployment rate, inflation, growth and interest rates.