MINNEAPOLIS (AP) -- Authorities are investigating after anti-Semitic graffiti was spray-painted on a Minneapolis school.

The vandalism happened at Lake Harriet Community School's Upper Campus in southwest Minneapolis. Photos posted online showed a swastika spray-painted on a school door along with a threat using an anti-Semitic slur.

Police say the vandalism happened sometime between Sunday and Thursday morning.

Minneapolis Public Schools Superintendent Ed Graff says the district ``condemns the anti-Semitic attack on our schools and community.'' Graff says the district is working with Minneapolis police to find out who painted the graffiti.

The Jewish Community Relations Council of Minnesota and the Dakotas says it has been in contact with school and law enforcement officials about the graffiti, and appreciated ``their swift response to this disturbing incident.''