International brand-name hotels have not been spared. The local Sheraton has a foot massage parlor on the fifth floor that has been shut down, and the spa next to the hotel has police seals on its doors. (A manager at the Sheraton said an outside company ran the spa, though a call to the spa’s phone number was answered by the Sheraton’s guest services department.)

The Ministry of Public Security has ordered police departments across China to carry out similar clampdowns. A joke making the rounds goes that to curb a recent surge in bird flu Mr. Xi said “get rid of chickens,” but the order was accidentally sent to the Public Security Ministry instead of the Health Ministry, and police officials thought that meant go after prostitutes.

So far, the biggest political casualty has been the Dongguan police chief, Yan Xiaokang, who has been dismissed and put under investigation. But it is the prostitutes who are facing the harshest consequences.

“This is the most serious campaign so far,” said a friend of Denny’s, a male prostitute with a trucker cap and black painted fingernails. “It’s the same everywhere, so we can’t even go to other cities.”

Before the crackdown, Denny’s friend said, he could make more than $100 on a good night. But he is now wary of contact from potential clients because they may be police officers “fishing” for people to arrest, and the clients have the same fears about making contact.

Early in the campaign, on Feb. 10, the Dongguan police announced that they had inspected nearly 2,000 entertainment sites in the city, had found 39 of them to be “yellow venues” (yellow is a slang term in China for erotic), and had arrested 162 people. In the first six days, according to the Security Ministry’s website, more than 2,400 yellow venues across the country were shut, 73 prostitution rings were broken and more than 500 people were detained.

The sex industry is more developed in Dongguan than in other Chinese cities, according to scholars, prostitutes here and the program on China Central Television, which drew wide criticism for showing prostitutes without obscuring their faces.