WASHINGTON — The Federal Reserve kept its options open on Wednesday, signaling that it would not raise short-term interest rates any earlier than June, while leaving unresolved how much longer it might be willing to wait before lifting its benchmark rate from near zero, where the central bank has held it for more than six years.

Treating the recent turmoil in markets as essentially meaningless noise, the Fed issued its most upbeat assessment of economic conditions since the recession, after its first policy-making meeting of the year, in a statement that noted solid economic growth and strong job growth.

But the optimistic tone was tempered by the Fed’s acknowledgment that inflation has slowed markedly in recent months and is likely to slow even more, making it harder for the Fed to determine how quickly to retreat from its stimulus campaign.

Fed officials for more than a year have pointed to the summer of 2015 as the likely time for the central bank to increase its benchmark interest rate, but investors are increasingly convinced that the sluggish pace of inflation will force the Fed to wait until fall at the earliest.