Sarah Tew/CNET

A pair of US senators are concerned that your smart TV might be spying on you.

Democratic Sens. Edward Markey and Richard Blumenthal asked the Federal Trade Commission to investigate whether internet-connected smart TVs are invading consumer privacy. The request was made in a letter sent to FTC Chairman Joseph Simons on Thursday.

The two senators expressed concern about how smart TVs track user viewing history and use that data to target ads toward consumers. By collecting information on what shows users watch and what applications they use to watch them, smart TV companies can come up with a pretty good idea about "users' preferences and characteristics," the letter said.

Consumers are often unaware of tracking features unless they read company policies closely. Smart TVs are so good at tracking users that they can allegedly identify users' political affiliations and views, according to the letter.

"The content consumers watch is private, and it should not be assumed that customers want companies to track and use information on their viewing habits," the senators wrote. "Users should be given the opportunity to affirmatively consent to the collection and use of their sensitive information, while still having access to the core functions of smart TV technology."

The FTC declined to comment.

Privacy issues surrounding smart TVs aren't new. The voice recognition on Samsung smart TVs could enable third parties to spy on you by tracking your watch history. Smart TV maker Vizio paid a $2.2 million fine for tracking and collecting users' viewing data last year. Many smart TVs and media streamers -- including some made be Roku, LG and Sony, among others -- may be tracking your viewing habits.

Markey and Blumenthal didn't immediately respond to requests for comment.

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