A Republican Minnesota state senator who was caught in a sting operation resigned under fire Thursday after he was charged with soliciting a minor for prostitution, stepping down before the Senate could vote on whether to expel him.

Republican Justin Eichorn, within hours of abandoning his seat in the state Senate, is scheduled to appear in federal court Thursday afternoon on allegations that he solicited prostitution from a Bloomington police detective posing as a 17-year-old girl.

Minnesota Senate Republicans on Thursday will make a motion to expel their colleague Sen. Justin Eichorn following a federal criminal charge that he attempted to solicit sex from a minor.