The US Justice Department and Federal Trade Commission have begun looking into Apple's new iOS subscription plan, according to sources speaking to the Wall Street Journal. The investigation is said to be in the early stages and may not go anywhere. European regulators are also saying they are keeping an eye on the situation.

Neither the DoJ nor the FTC would officially confirm the investigation, but people familiar with the matter said that Apple's subscription rules had at least landed on the radar of the two regulatory agencies. The European Commission didn't dance around the topic though—a spokesperson acknowledged that the Commission is "carefully monitoring the situation."

Apple only introduced its in-app subscription setup three days ago, following the launch of The Daily earlier this month. The system is available to all publishers of content-based apps, but anyone who sells a subscription outside of Apple's system must also sell it for the same price or less within Apple's system if they want to remain on the App Store. Additionally, they can no longer provide a link to an outside store from within the app, and when they use Apple's system to sell subscriptions, Apple gets to take a 30 percent cut.

The initial reaction from the creators of content-based apps was mixed—some were reportedly "relieved" that the terms weren't even worse, while others said they were beginning to look into their legal options. Last.fm co-founder Richard Jones recently joined Rhapsody in voicing his displeasure with the system, declaring that "Apple just f***ed over online music subs for the iPhone."

It certainly seems as if those who peddle streaming music and video apps are taking the new rules harder than those in the newspaper and magazine industries. The traditional media is apparently "used to paying a lot more than 30 percent for customer acquisitions," analyst Michael Gartenberg told Ars earlier this week.

Indeed, it's likely the music and video companies will be pushing the FTC and DoJ to continue the investigation, but they'll have to demonstrate that Apple has a dominant position in the market before a serious antitrust investigation can begin. There are, after all, other options—Google just rolled out its own system to set up recurring subscriptions called One Pass, and the company apparently plans to take a much lower cut of sales than Apple does.