The alternative rock band Wilco on Monday slammed Indiana’s new anti-gay “religious freedom” bill as “thinly disguised legal discrimination” in a tweet announcing that an upcoming concert in the state was canceled.

We’re canceling our 5/7 show in Indianapolis. “Indiana Religious Freedom Restoration Act” feels like thinly disguised legal discrimination. — WILCO (@Wilco) March 30, 2015

Wilco frontman Jeff Tweedy has been outspoken about LGBT rights in the past. Tweedy, a Chicago-area native, wrote a letter to his local newspaper in 2013 to urge Illinois residents to support passing same-sex marriage legislation.

Indiana officials over the weekend scrambled to contain the fallout from the newly enacted law, which critics say would protect business owners who refuse to serve gay couples because of religious objections. Top Republican lawmakers in the state said Monday that they plan to push for an amendment “clarifying” that the bill doesn’t allow for discrimination.