The International Council of Shopping Centers said that sales receipts for the week ending Saturday fell 0.6 percent after rising a lackluster 0.2 percent in the previous week.
Sales were down 1.8 percent from the same week last year, the trade group said in a weekly report released a day late due to the Labor Day holiday.
"The summer sales lull continued this past week as overall sales finished the fiscal month as of Aug. 31, 2013 on the softer side," said Michael Niemira, ICSC vice president of research and chief economist.
"Given the results for the month, ICSC research anticipates that retail sales will be within the 4.5 percent to 5.0 percent range when retailers report their month sales figures on ... Sept. 5," he said.
Niemira said there were gains notched in the week in some categories, including grocery, electronic, jewelry and book stores.