The United States is the only country in the world that allows the use of police dogs to terrify prisoners, says the Human Rights Record of the United States in 2006 issued on Thursday.

A Human Rights Watch report said five state prisons in the United States, including Connecticut, Delaware, Iowa, South Dakota and Utah, permit the use of aggressive, unmuzzled dogs to terrify and even attack prisoners in efforts to remove them from their cells.

Connecticut prisons were found to have used police dogs for nearly 20 times to take on prisoners. In Iowa State, 63 such cases were reported from March 2005 to March 2006, said the report.

Abuses in the U.S. prisons are common.

A U.S. government report, issued on Jan. 16, 2006, said that abuses of illegal immigrants happened in five prisons.

It was reported that the Florida State Prison used chemical agents against prisoners 238 times in 2000, 285 in 2001, 447 in 2002 and 611 in 2003 and 277 in 2004, which left 10 prisoners seriously injured and some with mental diseases.