LOS ANGELES, July 10 (Xinhua) -- U.S. Federal officials launched a nationwide advertising campaign against human trafficking on Thursday to get the public to help authorities rescue victims of the illegal trade.

    The outdoor advertising campaign is part of on-going efforts by the U.S. Immigration and Customs Enforcement (ICE) to raise public awareness about human trafficking in the United States.

    Federal officials put up billboards and signs at bus stops in Los Angeles and six other cities, with posters with the slogan "Hidden in Plain Sight."

    Earlier this year, ICE distributed video public service announcements to television stations in 30 media markets across the country. Like the billboards, the spots urge witnesses and victims to report the crime.

    The goal of the campaign is to alert the public about the existence of human trafficking in communities nationwide, said Robert Schoch, special agent in charge of the ICE office of investigations in Los Angeles.

    "As Americans celebrate their freedom this July, ICE is asking them to help us recognize and identify the victims of modern-day slavery who are in our midst," Schoch said. "These victims are domestic servants, sweat shop employees, sex workers and others lured here by the promise of prosperity, then forced to work without the ability to leave their situation."

    "ICE is committed to giving trafficking victims the help they need to come forward, so we can put an end to this reprehensible form of modern-day slavery," he added.

    Schoch said an estimated 800,000 men, women and children are trafficked across international borders each year and become casualties of the international sex trade and other forced labor situations.

    The victims typically find themselves in a foreign country, often unable to speak the language, with no one to help them. Traffickers often take away the victims' travel and identity documents and tell them that if they attempt to escape, their families will be physically or financially harmed, according to Schoch.

    One of the biggest challenges facing ICE and other law enforcement agencies is getting victims and witnesses to come forward, Schoch said.

    In addition to Los Angeles, the human trafficking billboards and transit shelter signs are being displayed in San Diego, San Francisco, Phoenix, Chicago, Baltimore and New York City. Other outdoor displays are planned for Houston, Miami and Washington, D.C., Schoch said.

    ICE is a member of the multi-agency Los Angeles Metropolitan Area Task Force on Human Trafficking, headed by the United States Attorney's Office.

    The Task Force's goal is to bolster ongoing efforts in the Los Angeles area to identify and rescue trafficking victims and prosecute those responsible for these crimes.