WASHINGTON – Superstorm Sandy drove the number of people seeking unemployment benefits up to a seasonally adjusted 439,000 last week, the highest level in 18 months.

The Labor Department said Thursday that weekly applications increased by 78,000 mostly because a large number of applications were filed in states damaged by the storm. People can claim unemployment benefits if their workplaces close and they don't get paid.

The storm has affected the claims data for the past two weeks and may distort reports for another two weeks, the department has said.