U.S. chain store sales (search) were mixed last week in an early sign of how Hurricane Katrina may have held back the economy.

Early evidence of how consumers are reacting since the storm hit was somewhat conflicting. One report showed growth in chain store sales and a second report posted no change, although they do not provide strictly the same week-on-week comparison.

Redbook Research (search) said sales at major retailers in September to date were up 0.2 percent compared with the same span in August and were 3.0 percent on a year-over-year basis for the week ending September 3.

The International Council of Shopping Centers (search) and UBS said that chain store sales were flat in the week to September 3 after dipping 0.3 percent the prior week.

Compared with the same week a year ago, sales were up 3.8 percent following a 3.9 percent increase a week earlier.

"The results for this past week reflect the fallout of Hurricane Katrina as national sales were held back by about one percentage point as stores were closed in the path of the hurricane," said Michael Niemira, ICSC's chief economist and director of research.