The number of Americans filing for unemployment benefits unexpectedly fell to a near 45-year low last week, but claims for six states were estimated because of Monday's Presidents Day holiday.

Initial claims for state unemployment benefits dropped 7,000 to a seasonally adjusted 222,000 for the week ended February 17, the Labor Department said on Thursday. Still the underlying trend in claims suggested job growth in February, which should continue to underpin the economy.

Claims for the prior week were revised to show 1,000 fewer applications received than previously reported. Claims fell to 216,000 in mid-January, which was the lowest level since January 1973. Economists polled by Reuters had forecast claims unchanged at 230,000 in the latest week.

It was the 155th straight week that claims remained below the 300,000 threshold, which is associated with a strong labor market. That is the longest such stretch since 1970, when the labor market was much smaller.

The labor market is near full employment, with the jobless rate at a 17-year low of 4.1 percent. Tightening labor market conditions are starting to push up wage growth, which could help to lift inflation toward the Federal Reserve 2 percent target.

Minutes of the U.S. central bank's Jan. 30-31 policy meeting published on Wednesday showed policymakers upbeat in their assessment of the economy and a number "judged that the continued tightening in labor markets was likely to translate into faster wage increases at some point."