Two members of the group appear in a video released Tuesday calling for a petition to drop the more than 400 arrests made last summer.
Watch the video:
[vimeo 88723558 w=500 h=281]
#SolidarityWisconsin from The Voice Project on Vimeo.
Protesters have sung in the Capitol rotunda nearly every day since 2011. The singing started during massive protests against Gov. Scott Walker's plan to take away collective bargaining rights for public workers.
Pussy Riot has gained notoriety for its protests against oppressive rule by the Russian government. Members of the group have spent time in jail on several occasions, most recently during the Winter Olympics in Sochi.
A Van Hollen spokeswoman questioned the group's comparison of Wisconsin to Russia.