San Francisco - Facebook will let people know when their friends are nearby via smartphone notifications, adding features for its growing base of mobile users.

Consumers can customise the tool, called Nearby Friends, to see a certain group of people for a set period of time, or turn it off completely, the Menlo Park, California-based company said yesterday in a blog post.

Friends will need to have the feature turned on in order to be seen.

Nearby Friends is Facebook’s latest move into location-sharing capabilities.

The world’s biggest social network has added the ability for its more than 1.2 billion members to check into places like they would on Foursquare Labs’ mobile application.

Facebook also has acquired Glancee, a location-tracking startup, and Gowalla, a location-based social network.

Foursquare, which popularised social location sharing, isn’t threatened by Facebook’s new service, chief executive Dennis Crowley said in a post on his Tumblr blog.

He cited a posting April 16 on the Verge technology news blog saying that people have accumulated many acquaintances on Facebook that aren’t their true friends.

“Facebook’s Foursquare-esque product launches (Facebook Checkins, Facebook Places, Facebook Nearby, Facebook Friend Finder, etc, etc) don’t concern me,” Crowley said.

Bloomberg News reported on Facebook’s plans to track users on their phones in February 2013.

In its blog post, Facebook said the new feature will be available for Apple’s iPhone and Google’s Android- based devices in the US “in the coming weeks.” - Bloomberg News