Four men who responded Wednesday to a prostitute’s ad on the website Backpage.com ended up rendezvousing with an undercover Portland police officer.

Jason T. Rickett, 31, of Gorham; Jack L. Chase, 50, of Buxton; Nicholas G. St. Amand, 29, of Gorham; and Andrew M. Woody, 50, of Westbrook were each arrested and charged with engaging a prostitute, a Class E misdemeanor punishable by up to six months in jail and a $1,000 fine.

Chase also was charged with assaulting the officer who posed as a prostitute, according to Portland Police Lt. James Sweatt.

In each case, the men arranged a meeting with the woman at a location in Portland, usually a hotel, although Sweatt declined to be more specific.

He said the department’s crime reduction unit has been targeting so-called “johns” who seek out prostitutes to pay for sex. This particular operation, he said, sought those who solicit prostitutes via the Internet.

Backpage.com is a website owned by Village Voice Media that connects consumers to a wide range of goods and services. It has frequently been used by prostitutes to find clients.

Sweatt said the operation is meant to reduce demand for prostitution, but it sometimes leads investigators to human traffickers.

“There are prostitutes who are not willing participants, who are being forced into this work and johns only support that market,” he said.

Rickett also was arrested in 2012 for engaging a prostitute.

He was among dozens of clients of Alexis Wright, a former Zumba dance teacher who was caught running a prostitution ring out of her studio in Kennebunk.