Washington, May 13 (IANS): An American man wanted by the Federal Bureau of Investigation (FBI) for "multiple incidents of sexual assault" between September 1995 and April 1996 involving minor girls, has finally surrendered after 23 years, the media reported.

Wayne Arthur Silsbee, 62, walked into the Oregon City Police Department and turned himself in, the FBI said on Sunday, adding that his motive behind the surrender was not immediately known, reports CNN.

Silsbee faces charges of first degree sodomy, first degree sexual abuse, endangering the welfare of a minor and first degree unlawful sexual penetration, according to a local arrest warrant the FBI said was obtained in Clackamas County, Oregon, near Portland, in July 1996.

The probe agency said it obtained a federal arrest warrant charging him with unlawful flight to avoid prosecution that was issued on September 1996.

Silsbee's first court appearance is scheduled for Monday.