The number of Americans filing new claims for unemployment benefits unexpectedly rose last week by the largest amount in three months, the Labour Department reported Thursday.
Applications were up by 25,000, to 471,000.
That was its first increase in five weeks and the biggest jump since a gain of 40,000 in February. Many economists had predicted a drop of around 4,000.
"Although no one expects this volatile series to go in one direction every single week, this is clearly a disappointment," said Jennifer Lee, senior economist at BMO Capital Markets.
Employers are hiring again — payrolls rose last month by 290,000 — but not at levels needed to make a dent in the unemployment rate, which increased in April to 9.9 per cent.
An improving economy has lured those who had given up looking for work back into the labour market.
The largest increase came in California, a rise of 8,351 because of layoffs in service industries and manufacturing. It was followed by Michigan, increasing by 3,175 because of layoffs in the auto industry.