BALTIMORE – In the coming weeks, Amazon.com is planning to expand its Prime Now service, with the promise of one-hour delivery to the Baltimore and Miami markets.

The launch in Baltimore coincides with the upcoming opening of a new Amazon distribution center near Canton, Md., writes the Baltimore Sun.

Baltimore and Miami join Manhattan as the cities where Amazon’s Prime Now one-hour delivery service is available. 

Amazon Prime's success has "petrified" local and national retailers, Howard Davidowitz, chairman of Davidowitz & Associates, told the Sun. "If you're a retailer and you're not scared of Amazon ... you should be," he said. "They are the change agent. They are leading the change in retail."

Amazon spokeswoman Kelly Cheeseman told the news source that Prime Now will expand to more cities this year. She noted that “tens of thousands of items” are available to order through Prime Now, mostly household staples such cleaning supplies, snacks, pet food, bottled water and diapers.

“Prime Now service is focused heavily on daily necessities. Stuff like bottled water, paper products, Kleenex,” Cheeseman told the Miami Herald. “Think about having a birthday party to attend in the evening, and you haven’t purchased a present, or running out of dog food or pet items. Members areloving the convenience of having it within the hour.”