Facebook is testing a new tool aimed at helping people get to know their neighbors and local communities, taking on social media app Nextdoor.

The world's largest social media website said Wednesday it's rolling out a feature with its mobile app called Neighborhoods in four US cities and Canada. Facebook users have to be at least 18 years old to use the new tool, which will allow people find neighbors who have common interests, discover local groups and businesses, participate in polls along with receiving and offering help to those in their communities.

The US cities include Charlotte, North Carolina; San Diego, California; Baton Rouge, Louisiana; and Newark, New Jersey. Facebook users already use the social network for these purposes through groups, but Neighborhoods combines all this information in one place.

Using Neighborhoods is optional and users will need to share their location to get matched to a neighborhood. Outside of sharing their Facebook profile information, users can also provide their interests such as skiing and there's also a section to get to know the pets in your neighborhood. People who use the feature could also take on different roles such as a "socializer," "helper" or "welcomer," she said. 

"We're not only showing people who lives in their neighborhood but how they relate to them and what these people are interested in and care about," Reid Patton, product manager for Facebook Neighborhoods, said in an interview. 

Canadians who already started testing the tool have used the feature to find missing pets, organize hiking trips, make new friends, find a handyman and get baking materials, Patton said. 

The new feature, available for both Android and iPhone users, could also create more challenges for Facebook, a platform that is already struggling to moderate the billions of posts that flow through its site. People also might be wary about giving even more data to Facebook, which has faced several privacy scandals. 

Facebook is also notorious for copying its competitors but social networking services that focus on neighborhoods such as Nextdoor have also grappled with its own problems such as racial profiling. Facebook will outline guidelines before a user joins Neighborhoods, noting that it wants to keep the online space "inclusive" and "safe," Patton said.

Every neighborhood will also have moderators to make sure people are staying within the guidelines and being kind, she said. Patton said users with accounts that are too new and people who have repeatedly violated the site's rules won't be allowed to use Neighborhoods. She didn't provide more details about the number of violations or how old the accounts have to be.

Users who are eligible to test out Neighborhoods will get a notification and a banner in the Facebook app encouraging them to try it out.

"We're really trying to see how neighborhoods is being used and the value people are getting out of it," Patton said. "We also hope to learn how we can better improve the product."