WASHINGTON – The number of Americans seeking unemployment aid plummeted last week to seasonally adjusted 339,000, the lowest level in more than four years. The sharp drop offered a hopeful sign that the job market could pick up.

The Labor Department said Thursday that weekly applications fell by 30,000 to the fewest since February 2008. The four-week average, a less volatile measure, dropped by 11,500 to 364,000, a six-month low.

Weekly applications are a proxy for layoffs. They can fluctuate sharply from week to week. If they stay near last week's level, it would likely signal better hiring ahead.