By 1995 it appeared that women from some surrounding countries were entering Cambodia. International concern was raised and some raids were carried out including one by the International Justice Mission (2004). This had the effect of displacing the workers. The number of prostitutes in Cambodia rose from about 6,000 at the time of the 1991 Paris Peace Accords, to over 20,000 after the arrival of UNTAC personnel in 1992, and declined to between 4,000–10,000 following their withdrawal. Cambodia has a child sex tourism problem. Some children are sold by their own parents, others are lured by what they think are legitimate job offers like waitressing. Pimps are reported to imprison young children who are virgins, not putting them to work until they have been presented to a series of bidders such as high-ranking military officers, politicians, businessmen and foreign tourists. Young girls working in brothels are in effect sex slaves. They receive no money, only food, and there are armed guards to stop them from running away. Children are often held captive, beaten, and starved to force them into prostitution. The United States Immigration and Customs Enforcement Agency has extradited American sex tourists back home for prosecution. Vietnamese child prostitutes make up one third of child prostitutes in Cambodia, and Cambodian brothels employ girls and women from Vietnam. Unofficial estimates in 2005 suggest there are as many as 15,000 prostitutes in Phnom Penh, and that up to 35% of them have been smuggled into Cambodia from China or Vietnam, mostly from the southwestern provinces of Vietnam (Long An, An Giang, Song Be, Kien Giang, Dong Thap, Can Tho and Ho Chi Minh City). Violence against prostitutes, especially gang rape, called "bauk" in Cambodian, is common. Perpetrators include customers and police officers. According to some sources, such assaults are not condemned by society due to the stigmatization of prostitutes – a survey on opinions on "bauk" showed that only 13 percent of the males and 13 percent of the females interviewed considered that sex forced by a group of men on a prostitute was rape. The most common response – 33.4 percent of males and 40.7 percent of females – was that bauk was dangerous because of the potential transmission of sexually transmitted diseases; 12.5 percent of males and 8.1 percent of females said that gang rape against prostitutes didn't hurt anyone because the women were prostitutes and saw many men anyway; while 12.7 percent of males and 16.7 percent of females said it was better that this happened to prostitutes than to other women.