PROVIDENCE — A convicted rapist who moved to Rhode Island from Massachusetts pleaded guilty yesterday to a charge of failing to register as a sex offender.

Michael DiTomasso, 35, of Woonsocket, entered the plea before Judge Mary M. Lisi in U.S. District Court, it was announced by U.S. Attorney Robert C. Corrente.

DiTomasso thus became the first person in Rhode Island convicted under a law passed two years ago that requires sex offenders who move to another state to register there. Assistant U.S. Attorney Milind M. Shah said the prosecution could have proved that DiTomasso pleaded guilty of rape, abuse of a child under 16, and abuse of a child under 14 in Worcester, Mass., in 1995.

Shah said DiTomasso moved to Woonsocket in February 2007.

Officer William Coupe of the Woonsocket police told DiTomasso in March 2007 that he was required to register with the Woonsocket police. Although DiTomasso lived within walking distance of the police station, he did not register.

The defendant was held pending sentencing Oct. 24. He could receive up to 10 years in prison and a fine of $250,000.