SAN FRANCISCO, United States -- Using a raised eyebrow or smile, people with speech or physical disabilities can now operate their Android-powered smartphones hands-free, Google said Thursday.

Two new tools put machine learning and front-facing cameras on smartphones to work detecting face and eye movements.

Users can scan their phone screen and select a task by smiling, raising eyebrows, opening their mouth, or looking to the left, right or up.

''To make Android more accessible for everyone, we're launching new tools that make it easier to control your phone and communicate using facial gestures,'' Google said.

The Centers for Disease Control and Prevention estimates that 61 million adults in the United States live with disabilities, which has pushed Google and rivals Apple and Microsoft to make products and services more accessible to them.

''Every day, people use voice commands, like 'Hey Google', or their hands to navigate their phones,'' the tech giant said in a blog post.

''However, that's not always possible for people with severe motor and speech disabilities.''

The changes are the result of two new features, one is called ''Camera Switches,'' which lets people use their faces instead of swipes and taps to interact with smartphones.

The other is Project Activate, a new Android application which allows people to use those gestures to trigger an action, like having a phone play a recorded phrase, send a text, or make a call.

''Now it's possible for anyone to use eye movements and facial gestures that are customized to their range of movement to navigate their phone - sans hands and voice,'' Google said.

The free Activate app is available in Australia, Britain, Canada and the United States at the Google Play shop.