Apple is facing mounting political pressure over claims that it has "systematically suppressed" news published by conservative outlets.
In a letter to the company published on Thursday, the head of the Federal Trade Commission called on Apple to review its policies, warning that companies that suppress or promote views based on ideology could be in violation of consumer protection rules.
The missive follows scrutiny of the tech giant's news app by the Media Research Center, a conservative media watchdog, which has accused Apple of a having a "defiant stance against offering news from right-leaning outlets".
A spokesman for Apple declined to comment.
Apple News, which offers users access to news stories from more than 3,000 publications, ranked as the most popular news app in the US, Canada and Australia, and the second most popular in the UK in January, according to the company.
