Facebook's Instagram added new features on Tuesday allowing users to exchange messages in private and group conversations as the photo and video-sharing service aims to keep up with messaging service Snapchat. With the changes,Instagram is trying to attract a young audience addicted to messaging with younger and hipper rival Snapchat, which has 100 million users and growing.

The new features mean Instagram users can share pictures directly with one friend or a group of people and send back text responses or pictures, which Instagram hopes will make users want to stay on its mobile app or web site longer.

Facebook launched its Messenger service as a standalone app earlier this year, and added a virtual assistant called 'M' last week that can complete tasks for users such as shopping.