The U.S. Labor Department said first-time jobless benefits claims jumped by 32,000 to 360,000 in the week that ended Saturday.
The department revised last week's estimate from 323,000 to 328,000, erasing some of the recent gains before the latest weekly figures even came in.
The four-week rolling average for the week rose by 1,250 to 338,000.
The largest increases in initial claims for the week ending May 4 were in Georgia with a jump of 2,212, New Mexico with 1,539 additional first-time claims and Kentucky with a gain of 892.
The largest decreases were in Connecticut with a drop of 1,434, New Hampshire with a drop of 867, and Massachusetts, where first-time claims fell by 756.