An 18-year-old US man in California who allegedly told police he had molested more than 50 children over several years was caught after confessing his crimes to his mother.

Joseph Hayden Boston claimed that since the age of 10 he had sexually assaulted victims in the cities where he had lived. Hours after allegedly molesting two victims on Saturday (2 December) he told his mother, who picked him up at 3am and turned him in to police.

Riverside Police said in a statement that Boston had allegedly molested two young boys aged 8 and 4 whom he "befriended" in a motel where he was staying.

The children were also staying in the facility - called Simply Home Inn & Suites - with their parents, but had been "allowed to go into the suspect's room."

In an update posted to Facebook on Saturday, US police elaborated: "Hours later, the suspect called his own mother stating what he had just done.

"Officers interviewed the suspect and he confessed to sexually assaulting the two juvenile victims in his motel room.

"He also admitted to molesting upwards of 50 children since he was 10-years-old in different cities where he had lived."

Boston had resided in Riverside since early November 2017 but previously lived in the Southern Californian cities of Lakewood and Buena Park, police said.

The suspect was booked into the Robert Presley Detention Centre with bail set at $1m. He was charged on suspicion of two counts of oral copulation on a child under the age of 10.

Protective services were called and took custody of both victim children.

Detectives from the Sexual Assault and Child Abuse Unit responded assisted in the investigation.

Law enforcement believe that Boston victimised other children who have not yet come forward. They are asking for anyone with information to contact local police.