HIGHLAND PARK, Ill. — A strike by teachers in Chicago's northern suburbs means classes are canceled for about 4,500 students in Highland Park and Highwood.

The teachers in North Shore School District 112 announced plans to hit the picket lines Tuesday after negotiations ended with no agreement. The district's students range from pre-kindergarten through eighth grade.

In a statement released early Tuesday, the union contends the district's latest offer would cause the highest salary for North Shore's teachers to fall behind 18 other districts in Lake County.