Economic expansion continues in most part of the United States, though the pace of growth has eased in the New York, Philadelphia, Atlanta and Chicago areas, the Federal Reserve said Wednesday.

"Reports from the twelve Federal Reserve Districts indicated that economic activity generally continued to expand since the last report, though a few Districts indicated some deceleration," the Fed said in the latest edition of the Beige Book.

The only district to show signs of accelerating growth during the April-May period was Dallas, whose economy has been buoyed by the strong oil and gas sector.

Economic activity was stable in the San Francisco, Boston, Cleveland and Kansas City districts.

"Looking forward, (business) contacts in most districts were generally optimistic about the outlook, although less so than the last report," the Fed said.

The Beige Book will be among the data reviewed by the Fed's monetary policy committee at its June 21-22 meeting.

In a speech Tuesday at the International Monetary Conference in Atlanta, Federal Reserve Chairman Ben Bernanke said he expects the U.S. economy "to pick up somewhat" in the second half of the year.

"Overall, the economic recovery appears to be continuing at a moderate pace, albeit at a rate that is both uneven across sectors and frustratingly slow from the perspective of millions of unemployed and underemployed workers," he said.