The number of Americans filing new claims for unemployment benefits unexpectedly rose last week, government data on Thursday showed, suggesting persistent weakness in the labor market after stumbling badly in recent months.

Initial claims for state unemployment benefits increased 6,000 to a seasonally adjusted 386,000, the Labor Department said. The prior week's figure was revised up to 380,000 from the previously reported 377,000.

Economists polled by Reuters had forecast claims dipping to 375,000 last week. The four-week moving average for new claims, considered a better measure of labor market trends, climbed 3,500 to 382,000.

Claims remain trapped in the tight band established since April and the lack of progress could indicate some fundamental weakness in the labor market. Job growth in May was the weakest in a year and followed a tepid peformance in April.