Amazon said Tuesday that it had acquired Ring, a maker of internet-connected doorbells and cameras, pushing more deeply into the home security market.

The deal is worth around $1.1 billion, according to a person briefed on the deal who would speak only anonymously because the terms were private.

Ring is best known for a doorbell with a security camera inside. The device allows homeowners to monitor visitors at their front door through an app on their phone, even if they’re not at home. Amazon has made home automation a major focus because of the success of its Echo family of products, which allow users to control thermostats, surveillance cameras and other connected devices using voice commands.

Amazon’s Echo Spot device already works with Ring doorbells, allowing people to look at footage from the cameras on the Echo Spot’s screen. Amazon had invested an undisclosed amount in Ring through its Alexa Fund, which finances start-ups that integrate their products with Alexa, the Amazon intelligent assistant that powers Echoes and other devices.