Pimps will traffic thousands of under-age prostitutes to Texas for Sunday's Super Bowl, hoping to do business with men arriving for the big game with money to burn, child rights advocates said.

As the country's largest sporting event, the game between the Green Bay Packers and the Pittsburgh Steelers will make the Dallas-Fort Worth area a magnet for business of all kinds.

That includes the multimillion dollar, under-age sex industry, said activists and law enforcement officials working to combat what they say is an annual spike in trafficking of under-age girls ahead of the Super Bowl.

The Super Bowl is one of the biggest human trafficking events in the United States, Texas Attorney General Greg Abbott told a trafficking prevention meeting in January.

Girls who enter the grim trade face a life of harsh treatment and danger, according to a Dallas police report in 2010. Few who emerge are willing to speak about it. Tina Frundt, 36, is an exception.

Now married and living in Washington D.C., Frundt was lured into sex work at 14 after she fell for a 24-year-old who invited her to leave home in 1989 and join his family in Cleveland, Ohio.

That family consisted of the man and three girls living in a motel. When Frundt declined on the first night to have sex with her boyfriend's friends they raped her.

I was angry with myself for not listening to him, so the next night when he sent me out on the street and told me ... (to earn $500) I listened, she said in a telephone interview.

Frundt paced the streets for hours and finally got into a client's car.

When she came home in the morning with just $50, her pimp beat her in front of the other girls to teach them all a lesson and sent her back onto the street the next night with the warning not to return until she had reached the quota.

The scenario was repeated night after night as Frundt's pimp moved his stable across the Midwest. Any sign of rebellion led to further beatings. Escape seemed out of the question.

I was a teen-ager in a strange town with no money and no place to go, she said. She finally escaped by getting arrested.

ENSNARED

Up to 300,000 girls between 11 and 17 are lured into the U.S. sex industry annually, according to a 2007 report sponsored by the Department of Justice and written by the nonprofit group Shared Hope International.

Some 90 percent of runaways and children whose parents force them to leave home fall into the trade and are often beaten, drugged, raped or imprisoned to force compliance, said a section of the report which referred to Atlanta.

Pimps tattoo girls with $ signs or the word Daddy and take them to unfamiliar cities where they are more vulnerable.

Typically, pimps recruit unwitting girls at shopping centers, mall events and on the Internet. Once ensnared, shame, fear and psychological manipulation by pimps make it hard to break free.

Clients, often called Johns, hook up with girls via the Internet, through hotels, massage parlors, strip clubs and escort services, the report said.

At previous Super Bowls, pimps hired cab drivers to turn their vehicles into mobile brothels, said Deena Graves, executive director of child advocacy group Traffick911.

Up to 10,000 adult and under-age girls have come to previous Super Bowls, said Jerry Strickland, communications director in the Texas attorney general's office, who acknowledged that precise figures are hard to gauge.

The statistics are a moving target. They (under age sex workers) can't be counted in turnstiles like ticket holders, he said in an interview.

RESCUE

Law enforcement agencies and advocacy groups rescued around 50 girls during the previous two Super Bowls, said Graves. Six were registered on the Center for Missing and Exploited Children website. One had been trafficked from Hawaii.

Even one rescue is considered a success, said Frundt who now advocates for exploited girls and has founded a girls' treatment center and a safe house for girls in Washington D.C.

To fight the trade, authorities, child welfare advocates and the airline industry are collaborating.

Representatives from American Airlines, Delta, United, Quantas and American Eagle are holding a training session to help them spot signs of trafficking. Nancy Rivard, president of Airline Ambassadors International, will also work with another 100 flight crews to distribute materials on flights.

Some 67,000 people signed a petition on www.change.org opposing sex trafficking as part of a campaign by Traffick911 called I'm Not Buying It! that is supported by 60 nonprofits and faith-based groups.

That campaign has also attracted heavy hitters like Dallas Cowboy Jay Ratliff, a three-time Pro Bowler, who made a public service announcement entitled Real men don't buy children. They don't buy sex.

Ratliff, who himself has two daughters, is recruiting other National Football League players for the campaign.

You hear of sex trafficking overseas, he wrote in an email from Hawaii where he is playing in the Pro Bowl. But you never imagine it is happening in the United States.