HUNTINGTON, W.Va. (AP) — Police in West Virginia are looking for two girls who didn't return home.

According to an Amber Alert posted Wednesday on the website for the National Center for Missing and Exploited Children, 6-year-old Cheylynn Dephia Jean Fortney and 14-year-old Cherity Hope Hannon of Huntington went missing on Sunday night.

Police say they believe 45-year-old Carl Ray Fortney took off with them in a white tractor-trailer. The truck with a Kentucky registration is labeled "Coretrans" with the cab number 679. Media outlets report Fortney is the girls' father and stepfather, respectively.

The website says the girls are believed to be in extreme danger and that information on their whereabouts should be reported to the Cabell County Sheriff's Office or West Virginia State Police.