Facebook is testing a mobile-ad network that would extend its reach by connecting advertisers with publishers of other mobile apps. The social network said Wednesday it had begun a test that will allow a small number of advertisers to use Facebook’s infrastructure to place ads on other apps. A spokesman declined to specify how many companies are involved or name them.

Facebook is testing its advertisements on outside mobile applications, calling it a new way for app developers to monetize their creations. The trial would pave the way for Facebook to open its own mobile advertising network, which would further boost its growing mobile ad revenue. ”We are running a small test to explore showing Facebook ads in third-party mobile apps,” Sriram Krishnan, who works on mobile products for Facebook, wrote on the company’s developers blog.