Facebook will unveil its plans for a mobile ad network, according to a report from re/code citing people familiar with the matter. 

Facebook will make the announcement at its F8 developer conference at the end of the month. 

The news comes after Facebook in January said it would begin testing advertisements in some third-party mobile applications. 

Those tests were limited to a few advertisers and partners, and Facebook did not say in which apps the ads were being tested. Still, they marked concerted efforts to continue generating revenue from mobile. 

Advertisting has been of concern for investors, particularly how the company would leverage its growing base of mobile users. 

According to Facebook's fourth-quarter earnings report, mobile advertising represented 54 percent of the company's total $2.34 billion in ad revenue for the quarter. 

Shares of Facebook were up approximately 2.5 percent Tuesday in early trading to $62.71. Facebook will announced its first-quarter earning tommorow, April 23.