Yahoo filed a massive patent infringement lawsuit against Facebook last month, claiming that Facebook’s News Feed, advertising methods, privacy settings and more infringed on its intellectual property. Facebook on Tuesday fired back at Yahoo with a countersuit, accusing the company of infringing upon 10 of its patents. Among its claims, the social networking giant says Yahoo’s Flickr photostream and its recent activity feature infringe a Facebook patent related to generating a personalized feed of stories on a social network. “While we are asserting patent claims of our own, we do so in response to Yahoo’s short-sighted decision to attack one of its partners and prioritize litigation over innovation,” Facebook general counsel Ted Ullyot said in a statement to Reuters. Facebook, the world’s largest social networking site, is in the process of its initial public offering that is expected to raise as much as $10 billion.