Authorities and a teachers' union are offering rewards for help finding a 23-year-old upper Manhattan school teacher who disappeared just days before classes began.

The United Federation of Teachers announced a $10,000 reward Friday, adding to a $2,000 reward offered by the New York Police Department's Crime Stoppers unit.

The union also sent counselors to the Thurgood Marshall Academy in East Harlem, where Hannah Upp was supposed to have started her second year of teaching Tuesday.

Police say Upp was last seen about 2:30 p.m. Aug. 29 as she left her apartment in the Hamilton Heights neighborhood.

Upp's roommates later found her keys, phone, ATM card, MetroCard, wallet and passport in her room.