MINNEAPOLIS (WCCO) — Sen. Al Franken is calling for an investigation into Apple’s new streaming music service. The Minnesota Democrat wants confirmation that the tech giant isn’t breaking anti-trust laws.

In a letter to the U.S. Attorney General and the FTC chairman, Franken warned that Apple Music may be hurting consumers by limiting competition and driving up prices.

Apple launched its streaming service last month to compete with Pandora and Spotify. But consumer rights groups have complained that Apple’s size and influence gives it an unfair advantage over rival music services, especially when it comes to reaching deals with musicians.

The FTC is already looking into Apple Music, but has not opened a formal investigation.