Three young Minnesotans are suing for the right to legally carry handguns in public, alleging that the state's minimum permitting age of 21 is discriminatory.

The lawsuit, filed Monday in U.S. District Court in Minnesota, argues that even though U.S. citizens who are 18 years old are considered adults "for almost all purposes," the state unconstitutionally bans them from carrying handguns outside their homes or automobiles for self-defense.

"There is simply no legal or constitutional justification that an entire class of adult citizens in Minnesota should be completely denied their fundamental, individual right to keep and bear arms," said Bryan Strawser, chairman of the Minnesota Gun Owners Caucus, which is also part of the lawsuit.

Strawser's nonprofit, in a statement late Monday, billed the suit as "the latest legal effort in the Caucus' planned litigation in Minnesota to secure the right to keep and bear arms throughout the state."

The three plaintiffs — Kristin Worth, Austin Dye and Axel Anderson — filed the complaint alongside the Minnesota Gun Owners Caucus, Second Amendment Foundation and the Firearms Policy Coalition. According to the lawsuit, they are also members of the respective groups.

They are suing Public Safety Commissioner John Harrington, Mille Lacs County Sheriff Don Lorge, Douglas County Sheriff Troy Wolbersen and Washington County Sheriff Dan Starry. The three sheriffs are being sued because they represent counties where each of the three plaintiffs live. Harrington's department manages permit-to-carry applications in the state, and applicants must file with their sheriffs.

A spokesman for the DPS said Tuesday that the department does not comment on pending litigation as a matter of policy. Reached by the Star Tribune, Lorge said in an e-mail that "I will be inquiring with our attorney on the matter."

Messages were also left seeking comment from Wolbersen and Starry.

The lawsuit describes the three Minnesotans' desire to legally carry handguns for protection — even detailing the make and model of the guns they would like to carry. Worth, an 18-year-old Mille Lacs resident who works part time managing a local grocery store, described wanting to carry a gun for self-defense because her work closing down the store at night often finds her traversing the store's dark parking lot alone.

Anderson, who is 18, works overnight shifts as a front-desk attendant at a Douglas County hotel. According to the complaint, his girlfriend was once accosted and chased through the hotel lot by a "group of unknown aggressors."

Blair Nelson, a Bemidji attorney who signed the civil complaint, argued in the filing that "arms carrying was a right available to all peaceable citizens" throughout American history. Nelson wrote that "hundreds of statutes from the colonial and founding eras" required people between 18 and 20 to keep and bear arms in cases of fieldwork and road and bridge construction. The lawsuit claimed that such laws also required arms carrying by members of the public to travel and attend church or court.

Nelson wrote that the three Minnesotans who filed the suit fear running afoul of state law that could lead to penalties ranging from $3,000 fines and a year of incarceration on first offense or up to $10,000 and five years incarceration on subsequent violations.

Staff writer Paul Walsh contributed to this report.