WASHINGTON — Specialty stores, department stores and general merchandisers all showed signs of weakness in September, as sales were flat or down for the month in those categories, the Commerce Department’s monthly report showed today.

But while those segments continued to lag, overall retail sales bounced back last month.

Sales at apparel and accessories stores were flat in September on a seasonally adjusted basis, coming in at $21.4 billion, while sales at department stores fell 0.7 percent to $12.8 billion. Sales at general merchandise stores, a category that includes department stores and discounters, declined 0.4 percent to $55.1 billion.

Non-store retail sales, which include Internet and catalog sales, posted an increase of 0.3 percent.

In the overall economy, sales rose 0.6 percent to $459.8 billion, mostly in line with economists’ expectations.