Six sexual offenders, including convicted child molesters and rapists, sued the city Wednesday to block a new ordinance that bans them from coming within 1,000 feet of parks, pools, playgrounds and other sites when children are present.

The six, including a college student who has joint custody of his 7-year-old son and has completed probation for child exploitation, are represented by the American Civil Liberties Union of Indiana, which filed the complaint seeking class-action status in U.S. District Court in Indianapolis.

The six allege the new ordinance is unconstitutionally vague, violates their 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.

Tenley Drescher, a deputy corporation counsel for the city of Indianapolis, said the city planned to litigate the matter to the end.

"We plan to vigorously defend the constitutionality of the ordinance," Drescher said. "The important part is protecting kids."