CHONGQING -- Police in southwest China have busted a brothel that catered to elderly men, most of whom have been left to live alone by their migrant worker children, local officials said Friday.

The brothel, disguised as a senior citizen recreation center in Bishan county in the city of Chongqing, had been operated by a local retired couple since May last year, police said.

Although the center was originally operated like a typical recreation center, the owners shifted to offering pornography to the elderly and accommodating prostitutes, police said.

Prostitution is banned in China, although the trade thrives in the guise of beauty salons, karaoke clubs and massage parlors in some cities.

Most of the customers were men above 60 who lived alone, police said, adding that their children work far from home, leaving their parents vulnerable to "bad influences."

The case, though extreme, highlights some of the challenges facing China's rapidly aging population. The centuries-old tradition of relying on children for support has been shaken by a surge of "empty nest" families, where elderly parents are left to take care of themselves after their children move away.

A recent survey conducted by the China Research Center on Aging found that 54 percent of elderly people in urban areas lived in "empty nest" families in 2010, while 45.6 percent of elderly people in rural areas lived alone. The figures were 49.7 percent and 38.3 percent, respectively, in 2006.

Only 12 percent of the 19,986 elderly people interviewed nationwide for the survey said they would be willing to stay in nursing homes. An overwhelming majority said they prefer to live in the communities they are familiar with and enjoy life with their relatives, even if the chances to do so are rare.