The American Civil Liberties Union and other groups have filed a lawsuit in San Francisco federal court seeking to stop a practice in which alleged illegal immigrants are shackled at the feet, waist and wrists while appearing in immigration court.

The groups allege in the suit filed Monday that a blanket policy that allows the immigrants to remain chained for up to 12 hours the day they're due in court violates constitutional bans against cruel and unusual punishment.

According to the lawsuit, the overwhelming majority of prisoners who show up in immigration courts have no violent criminal history. The lawsuit seeks to compel the Department of Homeland Security to make individual determinations about shackling rather than have a blanket policy. DHS officials declined to comment Wednesday.

The lawsuit applies only to immigrants appearing in San Francisco immigration courts. But attorneys who filed the lawsuit said Wednesday that they hope it prompts changes to the system in other cities.

"We'd like to convince them to follow their own policy and at least add some humanity to it and recognize it's a painful and hurtful thing to shackle people like that," said Paul Chavez, senior attorney for the Lawyers' Committee for Civil Rights in San Francisco, one of the groups who filed the lawsuit.

The groups allege that shackling everyone at an immigration hearing amounts to cruel and unusual punishment. The lawsuit seeks class action status to represent prisoners transported to and appearing in immigration court in shackles in San Francisco.