U.S. Sen. Al Franken, D-Minn., is raising privacy concerns with Pokémon Go, a new smartphone game that millions of users around the country have downloaded in the past week.

The game blends the real world and virtual world using GPS cellphone technology, but it also seeks access to the user's personal data, like precise location, e-mail address and the last website visited.

The game has been downloaded 7.5 million times in less than a week. Franken noted that many of the users are children. Franken has asked Niantic, the company that developed the game, to explain how it collects user data and what it does with that data. He expressed concerns that the company was collecting and distributing to third parties more personal information than was necessary to keep the app functioning.

Reports that Pokémon Go had in some cases allowed its producer complete access to users' Google accounts, including e-mail, led to plans for a software fix, Franken explained, but he said the fix needs to take place "swiftly."

In addition, the top Democrat on the Senate Privacy and Technology Subcommittee laid out a series of detailed questions whose answers should reveal exactly what personal information Niantic is collecting and with whom it is sharing the data.

"Americans have a fundamental right to privacy, and that right includes an individual's access to information, as well as the ability to make meaningful choices, about what data are being collected about them and how the data are being used," Franken wrote in a letter to Niantic CEO John Hanke. "As the augmented reality market evolves, I ask that you provide greater clarity on how Niantic is addressing issues of user privacy and security, particularly that of its younger players."

As it stands, Pokémon Go requires users to opt out of sharing their personal information. Franken asked if Niantic would consider changing to an opt-in system whereby users have to agree to have their personal information collected. Franken also wants Niantic to explain how — or if — it gets the informed consent of parents before collecting personal data on their children.

Niantic shares users' personal information with "third party service providers." Franken asked for the names of those third parties.

Answers to Franken's questions are due by Aug. 12.

Jim Spencer • 612-270-1266