SAN FRANCISCO: Facebook on Friday took direct aim at video-loving adolescents, and Snapchat, with the release of a new iPhone app that allows teens to watch clips about the lives of their classmates.

The app, called Lifestage, was released with no fanfare, and is available for anyone to download on iPhone, although seeing profiles of other users is reserved for those 21 years of age or younger.

The social network allows users to make video clips to describe likes, peeves, dance styles, and other aspects of their character.

Those clips are woven together to serve as public profiles that can be viewed by other Lifestage members, provided they are young enough.

A tool in the app lets users block and report older folks.

"Lifestage makes it easy and fun to share a visual profile of who you are with your school network," the app's iTunes store description says.

Once enough students at any given school are on the app, it becomes "unlocked".

"Once your school is unlocked, you can access the profiles of others in your school community (and all over!) so you can get to know people better in your school and nearby schools," the description said.

Lifestage users are invited to share video snippets whenever they wish.

The app comes as a challenge to Snapchat, the vanishing message service that became a hit with teenagers and which lets members share pictures and video clips.

Lifestage was seen by some as an effort by Facebook to stay connected to young internet users disinclined to take part in the leading social network.

Facebook did not return an AFP request for comment.

Earlier this month, Instagram put its own spin on a key Snapchat feature by letting users post "Stories" that eventually vanish from the Facebook-owned photo-and video-sharing app.

Instagram Stories encourages people to share ephemeral collages of everyday moments on the app which has built a reputation for allowing people to post highlights from their lives or artistic works.