At least 13 percent of inmates in U.S. prisons have suffered from sexual assaults, says the Human Rights Record of the United States in 2006 issued here on Thursday.

Besides, many inmates have suffered frequent sexual abuses, a report by the United Nations Committee Against Torture said on May 19, 2006.

It estimated that nearly 200,000 inmates currently in prisons were or will become victims of sexual violence. The number of prisoners who had suffered sexual assaults over the past 20 years is likely to exceed one million.