By Mary Wisniewski
CHICAGO (Reuters) - MasterCard said on Tuesday that its credit cards can no longer be used to pay for ads on the Backpage.com website, following a request from a Chicago law enforcement official who said the site is used by sex traffickers.
Cook County Sheriff Thomas Dart said that so-called "escort" ads on Backpage.com and similar sites make up the foundation of the sex trafficking industry, which preys on the young and vulnerable. He has asked both Visa Inc and MasterCard Inc to cut off any association with the Backpage.com "adult" section.
"Backpage has significantly lowered the barrier to entry for would-be traffickers," said Dart, adding he will reveal details of a larger initiative against Backpage at a news conference on Wednesday.
MasterCard spokesman Seth Eisen said in an email that the company has rules that prohibit its cards from being used for illegal or brand-damaging activities.
Backpage is a classified advertising website that offers forums to find roommates and sell goods, like other sites, but its primary revenue stream is through its adult page, according to Dart's office.
An attorney for Backpage.com was not immediately available for comment.
Cook County Sheriff's police have made more than 800 arrests since 2009 stemming from Backpage ads, including an arrest for juvenile sex trafficking just last month, according to Dart's office.
American Express Co has already stopped allowing its credit cards to be used for "adult" ads on Backpage.com, company spokeswoman Sanette Chao said.
"We can terminate card acceptance for any merchant that we deem harmful to our brand, illegal or high risk," Chao said.
The only remaining options to pay for Backpage adult ads are Visa credit cards and bitcoin, an electronic currency, a spokesman for the sheriff's office said.
No response was immediately available from Visa.
(Reporting by Mary Wisniewski; Editing by Eric Walsh)