Amazon has bought an Andover, Massachusetts-based company that makes internet-connected doorbells and security cameras.

Blink announced on its website Friday it was being acquired by the Seattle e-commerce giant. Terms of the deal haven't been disclosed.

The move could help Amazon compete in the fast-growing home security camera market and against similar devices made by Nest, a subsidiary of Google parent company Alphabet.

Blink tells customers "nothing changes for now" as it continues to sell its own recently launched products under the Amazon umbrella.

"We'll continue to operate under the Amazon umbrella," Blink said in a blog post.

"It's Day 1 for us at Amazon, and we're looking forward to seeing what we can deliver to our customers together."

The U.S. startup last week added video doorbell priced at $99 to its home security system offerings. It also launched a new Amazon Key service for people in some U.S. cities to allow a door to be unlocked when they're not home so packages can be left inside.

Each Key kit includes an Amazon Cloud Cam synched to the internet and a smart door lock from either Yale or Kwikset. Prices for kits start at $250, according to Seattle-based Amazon.

Prime members with the service can use a smartphone application to track packages and then watch deliveries happening or review video of in-home drop-offs, the company said.

Key allows someone making a delivery to request access to the recipient's home, with Amazon checking to make sure the proper driver is at the right location at the intended time before unlocking doors, according to a description of the service.

A Cloud Cam providing a view of the inside entryway goes into action when doors are unlocked, recording a delivery. Delivery people will not be given access codes, as unlocking doors will be done via the internet.

Amazon said it is working on partnerships with professional service providers such as cleaners, pet sitters, and dog walkers to allow Key to be used to allow them access into houses as desired by customers.

U.S. retail giant and staunch Amazon rival Walmart late this year began testing its own in-home delivery in collaboration with a company specializing in smart cameras, doorbells, and locks.

Expanding into home security opened a new competitive front with Google's parent company Alphabet, owner of Nest Labs which has a line of new products aimed at that market.