INDIANAPOLIS -- The ACLU of Indiana filed suit on Wednesday against Indianapolis on behalf of six sexual offenders over the city's ordinance aimed at child molesters found near playgrounds or in the presence of children.

The group said the ordinance is unconstitutional on grounds that it might violate the 14th Amendment guaranteeing due process.

The ordinance prohibits sex offenders who are convicted of crimes against children from being within 1,000 feet of playgrounds, recreation centers, swimming pools, sports fields or other facilities when children are around.

The ban includes an exception if an adult with no history of sex crimes is with the offender.

The six people involved in the suit include a college student who has joint custody of his 7-year-old son and has completed probation for child exploitation.

The suit contends that the new ordinance is vague, violates offenders rights to vote and attend church, and prevents them from freely traveling on streets and highways that may pass within 1,000 feet of the affected sites. They are seeking temporary and permanent injunctions barring the city from enforcing the new law.

"It is virtually impossible to travel through the streets and interstate highways in Marion County without passing within 1,000 feet of a playground open to the public, recreation center, bathing beach, swimming pool or wading pool, sports field or facility," the complaint said. "Moreover, there is no way for a person to know if he or she is passing within 1,000 feet."

The ordinance cleared the City-County Council by a 25-2 vote on May 15 and took effect immediately. It carries fines of up to $2,500 for violations.

The law includes an exception that permits sex offenders to visit those sites as long as they are with another adult who is not a convicted sexual offender.

The plaintiffs are identified only as John Does in the complaint. The father of the 7-year-old boy attends Indiana University-Purdue University-Indianapolis and said he cannot travel to classes without passing within 1,000 feet of a banned site. He also works in an office within 1,000 feet of a city park with a playground.

Another plaintiff, a convicted rapist, attends a church that recently opened a recreation center. Both he and a third plaintiff say the new law prevents them from attending their polling places on Election Day.

The Associated Press left a message with the city's legal office seeking comment on the lawsuit.