Three schools in Bergen County were evacuated Wednesday and several other schools in northern New Jersey will be closed Thursday due to a bomb threat.

Officials say a computer-generated letter was mailed to the mayor of Emerson. There were reports the threat specifically mentioned Thursday morning. As a precaution, district officials evacuated Emerson Memorial High School, Villano Elementary School and Emerson Junior-Senior High School.

The following districts will be closed Thursday as a precaution:Emerson: 4 schools - 3 public, 1 catholic Oradell: 5 schools - 1 grammar, 2 catholic, 2 high schools (shares middle school and high school with River Edge)River Edge: 4 schools - 2 grammar schools, 1 catholic, 1 middle schoolCloster: 8 schools Demarest: 6 schoolsHaworth, Harrington Park, Northvale, Norwood: 7 schoolsOld Tappan: 3 schools - 2 grammar schools, 1 high schoolRiver Vale: 3 schools - 2 grammar, 1 middle schoolWestwood: 7 schoolsWashington Township: 90-minute delay

Emerson district officials expect the schools to reopen Friday.

Meanwhile, bomb squads were searching schools in Emerson and other districts.