The number of out-of-work Americans seeking initial unemployment benefits rose unexpectedly by 3,000 last week to the highest level in nearly two months, the government said on Thursday.

The Labor Department (search) had to estimate jobless claims counts from Mississippi and Louisiana since officials were unable to contact offices in the two hurricane-stricken states, a department analyst said.

According the report, first-time jobless claims climbed to 320,000 in the week ended Aug. 27 from an upwardly revised 317,000 the prior week.

Economists, on average, had expected claims to come in at 315,000, unchanged from the prior week's original reading.

While last week's numbers showed no effects from Hurricane Katrina (search), which hammered U.S. Gulf Coast states on Monday after blowing through Florida over the weekend, its aftermath will likely skew the data in the weeks ahead.

Economists expect the deadly storm's toll on jobs and consumption to be severe, at least in the short run.

Before Katrina battered the region, claims figures had shown the U.S. labor market stabilizing at healthy levels.

Economists estimate the number of workers on U.S. payrolls grew a healthy 190,000 in August but financial markets may be more focused on the September number as they assess the economic impact of the storm.

Labor releases its employment report on Friday.

The four-week moving average of claims, seen by many economists as a better guide to the employment situation because it irons out weekly volatility, rose for the third straight week, to 316,750 from 315,500 the previous week.

The number of people still on the rolls after drawing a week of benefits rose to 2.61 million in the week ended Aug. 20, the latest period for which the data are available.