WASHINGTON (AP) – U.S. soldiers visiting brothels may have encouraged sex slavery in South Korea because of a lack of understanding about human trafficking, the Defense Department’s inspector general concluded in a report.

Investigator Joseph E. Schmitz found that military patrols were sometimes overly friendly with bar owners and often didn’t report cases of sex slavery and prostitution because of a misperception that they could only report them if they had hard evidence.

The report obtained Thursday by The Associated Press said that because of this misperception, “commanders sometimes did not take the necessary steps to place establishments off-limits.” It recommended more education to help U.S. troops identify possible instances of human trafficking.

The investigation about whether U.S. troops have participated in or given business to the human trafficking industry was requested by 13 members of Congress after an April 2002 report by a TV station.

An investigative reporter at WJW, a Fox affiliate, filmed U.S. military police patrolling bars and brothels in South Korea. Officers told the reporter that the women at the bars had been forced into prostitution and that they were patrolling the establishments at their commanding officers’ request to intervene if soldiers got into trouble.

The lawmakers raised concerns about whether U.S. soldiers were unwittingly helping to support the human trafficking industry.

Rep. Christopher Smith, R-N.J., who has authored legislation to help countries catch people who trade human beings, said Thursday that problems have developed because of a lack of understanding of human trafficking that has developed since the end of the Cold War.

“There’s been a learning curve and a sense of disbelief, that somehow these women were prostitutes by their own volition” instead of being coerced into prostitution, Smith said. “They’re sold just like slaves were years ago in this country.”

As a result of the investigation, U.S. military officials in South Korea have made an additional 26 establishments suspected of being involved in prostitution and human trafficking off-limits to U.S. servicemen. They also have increased educational efforts for all service members on how to spot instances of human trafficking.

The report recommended that the military create a standardized human trafficking curriculum; make improvements to on-base entertainment and recreational facilities; and continue coordination efforts with South Korean law enforcement officials.

Smith called the military’s response to the problems “a remarkable story” and said he hopes U.S. military leaders worldwide will use it as a model to fight prostitution.

A separate investigation on prostitution and human trafficking issues at U.S. bases in Bosnia and Kosovo is ongoing.

The State Department estimates that about 4 million victims, mostly women and children, are taken each year and sold into the sex trade or forced labor. About 50,000 are trafficked into the United States, mainly from Russia, Ukraine, Poland, Latin America and Southeast Asia.

AP-ES-08-07-03 1923EDT