Facebook, the social network giant, is set to launch mobile advertisements in a few weeks, according to Financial Times report on Monday.The move will tap new source of revenue for the social network before its initial public offering expected in May.Facebook said it plans to raise 5 billion dollars, which analysts said will likely change in an IPO that could value the company at between 75 billion to 100 billion dollars.In its filings with the U.S. Securities and Exchange Commission last week, Facebook made it clear to potential investors that it plans on putting a lot of focus on its mobile users.Of the company\'s 845 million members, 425 million monthly active users access the site with their mobile devices.The report said Facebook has been in contact with unidentified advertising agencies for displaying what it calls \"featured stories\" in the users\' news feed.The ads reportedly would launch in early March.As other internet companies are facing mounting pressure to make mobile pay, analysts said Facebook has got to figure out a clever way of monetising it, with more and more people spending more time accessing the internet via mobile devices.