SAN FRANCISCO: Instagram said Wednesday it now has more than one billion active users, as it unveiled a new long-form video feature in a bid to attract "creators" like those on YouTube.

It becomes the fourth Facebook platform to hit the billion-user mark, including the namesake social network with more than two billion users, and the messaging applications WhatsApp and Messenger.

Instagram, which had some 800 million users as of September, has been outpacing rival social networks such as Twitter and Snapchat and has been gaining younger users even as Facebook itself has seen declines in the youth segment.

Instagram chief executive Kevin Systrom announced the milestone as he unveiled the new video application known as IGTV.

"We have now a community of one billion users," Systrom told the event in San Francisco.

"Since our launch in 2010, we've watched with amazement as the community has flourished and grown."

As Facebook itself has moved deeper into video, Instagram will become a direct competitor to YouTube with IGTV.

IGTV will enable any user to upload long-form videos and will also include "channels" from video "creators," similar to a format employed by Google-owned YouTube which has given rise to a number of YouTube "stars."

"Anyone can be a creator -- you can upload your own IGTV videos in the app or on the web to start your own channel," Systrom said.