WATERVILLE, Maine (AP) — Police in Waterville, Maine, say a mother who lost custody of her two children has disappeared with them.

Police say 34-year-old BethMarie Retamozzo was allowed to load 7-year-old Joslyn Retamozzo and 6-year-old Joel Retamozzo into her van during a supervised visit with the understanding they would meet the supervisor at a park.

Police say the three didn't show up Thursday. Authorities say they were last seen in the mother's van, which had a New York license plate. Retamozzo also was legally traveling with her 2-year-old child.

On Friday, police obtained an arrest warrant and said they're concerned about the children's welfare.

The Waterville Police Department has enlisted the assistance of a number of agencies including the National Center for Missing and Exploited Children in an attempt to locate them.