Dive Brief:

• Amazon will extend free same-day delivery to Prime members in certain zip codes in several cities, the company said Thursday.

• More than a million items will be eligible, a minimum order of $35 is required, and orders must be in by noon. The service is now available seven days a week in Atlanta, Baltimore, Boston, Dallas, Indianapolis, the Los Angeles metro area, New York, Philadelphia, Phoenix, the San Francisco Bay area, San Diego, Seattle, Tampa Bay, FL, and Washington, DC.

• Prime members already enjoy free two-day shipping on some 20 million items, with no minimum order, and in many areas also are privy to same-day shipping for $5.99.

Dive Insight:

This is a small, limited but very strong advance for Amazon in the same-day delivery space. The move increases the lengthy list of benefits to Prime members, making the service that much more attractive to anyone who hasn’t yet signed up.

And it could help solidify the definition of same-day deliveries, at least for retail (as opposed to grocery or restaurant). The sweet spot may be found in orders before noon, with delivery coming later in the day. The service will likely have to expand to more items in more areas, but this is a significant salvo and turns up the heat on the competition even more.

To meet the needs of its expanding fulfillment offers, the e-retail giant this week said it needs some 6,000 new full-time workers in its warehouses and distribution centers across the U.S.