Facebook on Tuesday announced it is rolling out improvements aimed at letting users be more selective about who gets to see what they post at the world's largest online social network.

The move came in the face of a challenge from a freshly launched Google+ social network, which has won legions of fans by allowing people to share content based on which "circles" friends fall into.

"We're announcing a bunch of improvements that make it easier to share posts, photos, tags and other content with exactly the people you want," Facebook's Chris Cox said in a blog post.

"You have told us that 'who can see this?' could be clearer across Facebook, so we have made changes to make this more visual and straightforward," he continued.

The main change at Facebook will be moving controls from a settings page to places next to posts, photos and tags so people can make decisions about sharing while looking at content they are about to send to profiles.

Changes will also make it easier for Facebook users to understand who can see their online content and how it appears to others, according to Cox.

"These changes will start to roll out in the coming days," Cox said.

"Taken together, we hope these new tools make it easier to share with exactly who you want, and that the resulting experience is a lot clearer and a lot more fun," he added.

Google is a latecomer to social networking but its new site, Google+, has grown rapidly to more than 10 million members since its launch on June 28.

In unveiling Google+, Google stressed the ability it gives users to separate online friends and family into different "Circles," or networks, and to share information only with members of a particular circle.

One of the criticisms of Facebook is that updates are shared with all of one's friends unless a user has gone through a relatively complicated process to create separate Facebook Groups.

While Google+ may be the fastest-growing social network ever, it remains to be seen whether it can pose a serious threat to the social networking titan Facebook, which has more than 750 million members.

Google has a billion users worldwide that could be drawn into the California-based Internet giant's social network.