The Federal Trade Commission reportedly is reviewing whether Twitter has engaged in anticompetitive activity against Pasadena-based app developer UberMedia, according to media reports.

UberMedia develops and has acquired apps for various computer and cell phone platforms that aim to provide a more efficient means to send, receive and sort Twitter messages. San Francisco-based Twitter has taken steps in recent months to retain greater control over its user base so as to not lose potential advertising and other revenue opportunities on the Internet instant messaging service.

UberMedia, a spinoff of tech incubator Idealab, recently lost a bidding war with Twitter over the popular TweetDeck app for desktop computers. In February, Twitter blocked certain UberMedia apps from accessing the service for several days, claiming that UberMedia had violated “several provisions of their terms of service.” In response, UberMedia has threatened to launch its own competing messaging service.

The agency’s review of Twitter was first reported by Business Insider blog on Thursday, but the Wall Street Journal, Bloomberg and others have since published stories citing their own sources. Spokespeople for the FTC and Twitter declined to comment. UberMedia confirmed that it had been contacted by the FTC but declined to provide details.