File photo: Independent Media

Moscow - A Russian man who abducted a nine-year-old boy and raped him over the course of a decade was sentenced on Monday to 20 years in prison, state media reported.

"The accused confessed his guilt during the preliminary investigation," the country's top investigative agency said in a statement.

The man lured the victim to his Moscow apartment in July 2007 and confined him to a room, out of view of the neighbours, the Investigative Committee said.

The crime was discovered a decade later, by which time the victim was 19 years old, Russian state news agency RIA Novosti reported.

"The child was regularly sexually abused," the report said, adding that as an adult the victim was unable to remember his parents.

Russian broadcaster NTV said the victim was being provided with psychiatric help.

The boy was in a difficult situation when he was abducted, already smoking cigarettes and drinking alcohol, and having repeatedly run away from home, the broadcaster said, citing the missing person's report.

The Investigative Committee said the boy had simply agreed to live with the man when he initially went to the apartment.