OMAHA, Neb. — There's a dark, little-discussed side to large groups of people gathering for big sporting and other events — from the Olympics to the Super Bowl to the annual College World Series in Omaha.

It is an increase in human trafficking, particularly sex trafficking.

During the June 14-24 baseball tournament, Catholic-related groups and other organizations planned to lead prayer sessions to raise awareness and bring the power of prayer to the issue.

The prayer series is an ecumenical effort supported by the Archdiocese of Omaha.

"The CWS is an exciting event for Omaha, but sex trafficking increases, with young girls trafficked into our hotels and motels," said Sister Celeste Wobeter, a Notre Dame Sister who helped organize the prayer series, with representatives of a number of faiths leading sessions in two-hour blocks from 6 a.m. to 10 p.m. at a Salvation Army chapel.

People have been invited to join in the prayer at the chapel at any time, for whatever length of time they can, Sister Wobeter said. A website was created for the effort: http://traffickprayerseries.com.

Sister Wobeter said she is a member of a local committee dedicated to combating human trafficking that also includes the Servants of Mary and Catholic Charities. And the archdiocese has been drawing attention to the issue, including sponsoring an April 22 conference on human trafficking in Omaha that drew more than 90 representatives of parishes, homeless shelters, religious orders and several religious denominations.

Mary Beth Hanus, victim outreach coordinator for the archdiocese and director of its anti-pornography committee, encouraged people to participate in the College World Series prayer effort.

"It's one action that can assist all of us as we address this issue," Hanus said.

Among groups signed up to lead sessions were the Notre Dame Sisters, Pope Paul VI Institute and St. Pius X Parish, all in Omaha.

Interreligious campaigns against human trafficking have been held around the world in recent years, including sites for the Super Bowl, the Winter and Summer Olympics and the World Cup.

Efforts against human trafficking will continue to grow in Omaha, Sister Wobeter said. People concerned about the issue, for example, plan to continue lobbying the Nebraska Legislature for harsher penalties for  human trafficking, and in the future to line up educational opportunities for hotel and motel officials as a way to provide tips on spotting human trafficking activity.

And prayer is important and powerful, Sister Wobeter told the Catholic Voice, Omaha's archdiocesan newspaper.

"We hope it can make a difference in the lives of these young girls," she said.