Omnicom Group Inc's media services division signed a deal worth $230 million with Twitter Inc that will integrate Omnicom's automated ad buying unit Accuen with Twitter's mobile ad exchange MoPub.

The two-year deal will lock in ad rates and inventory access for Omnicom agencies and will also give Omnicom a "first look" at new ad units and opportunities being developed by the microblogging site.

The Wall Street Journal reported the deal first. (link.reuters.com/xyj69v)

"This is the first holding company agreement we've done on the mobile ad exchange side," Adam Bain, Twitter's president of global revenue, told the newspaper.

Twitter confirmed the deal but declined to comment further.