NORRISTOWN The Montgomery County District Attorney's Office and two police departments are teaming to investigate sex trafficking and prostitution in hotels and motels in King of Prussia and Montgomeryville, authorities announced Friday.

"Public safety and quality-of-life issues relating to the illegal commercial sex trade and human trafficking are of growing concern in Montgomery County," District Attorney Risa Vetri Ferman said in a statement.

The concern over sex trafficking and prostitution rings is so great, Ferman said, that she, Upper Merion Police Chief Thomas Nolan, and Montgomery Township Chief Scott Bendig took the unusual step of publicizing the operation before it starts to educate the public and hotel workers about the damage to people and communities these activities cause, and to dissuade those who might use the hotels for illegal activities.

Law enforcement authorities say commercial sex crimes have been on the rise in Upper Merion Township's King of Prussia and Montgomery Township's Montgomeryville.

Between 2011 and 2013, Upper Merion saw a 56 percent increase in prostitution crimes, police said. Greater activity has been reported by hotel and motel managers who suspect prostitution is taking place, said Upper Merion's Nolan.

"We don't want to make it seem, 'Don't come to an Upper Merion hotel because there is prostitution all over.' We're trying to be proactive before it gets out of hand," Nolan said.

Montgomery Township police say that prostitution and related offenses have been occurring more frequently since 2009.

Police efforts in both townships initially will center on hotels and motels that might be used as hubs for sex crimes, and will include undercover stings against customers.

Since sex workers fly in from around the country or from overseas and customers are locals, Nolan said, "We're trying to cut off the flow of customers," Nolan said.

When the joint law enforcement operation begins within a month, authorities especially will be looking for sex trafficking, a form of human trafficking in which a person is forced into the sex trade and prevented from leaving it.