Initial claims for unemployment benefits rose to 383,000, climbing above the previous week's revised estimate of 373,000.
The four-week rolling average, which gives a steadier indication of the direction of jobless claims rose by 3,750 to 374,500.
The largest increases in initial claims for the week ending May 19 were in California (up by 2,716), Texas (up by 1,648) and South Carolina (up by 1,029).
The largest decreases were in Wisconsin (off by 1,240), Michigan (off by 716) and Georgia (off by 691).
The U.S. unemployment rate is 8.1 percent, falling 0.1 percentage points from March to April.
The unemployment rate could be revised Friday with the release of the Labor Department's employment situation report for May.