CHICAGO (CBS) — All schools in Porter County, Indiana, as well as the Lake Central School Corporation schools in neighboring Lake County are closing at least until mid-April to help reduce the spread of the novel coronavirus.

Porter Township School Corporation Supt. Stacey Schmidt announced Friday that she and the heads of all six other school districts in Porter County have decided to close all of their schools for four weeks, starting Monday. Officials plan to reopen the schools on April 13.

Schools in Munster, Ind., Hammond, and Crown Point also announced that school will be closed. Munster and Crown Point will be closed until April 13, while Hammond will be closed until April 6.

“The situation is extremely fluid and the date may be extended as we reassess the situation during the duration of the closure. Porter County administrators, in consultation with the Porter County Health Department, will reconvene on April 3, 2020, to reconsider future plans,” Schmidt wrote in a letter to parents.

Remote learning assignments for all students will be posted online on Mondays, Wednesdays, and Fridays while schools are closed.

All extracurricular activities, including sports, also have been postponed until schools reopen. School buildings and facilities will be closed to the public, and all facility rentals are postponed until schools reopen.

Meantime, Lake Central School Corporation also has announced its schools will close for four weeks, starting Monday. Supt. Larry Veracco said teachers will begin posting remote learning lessons online on Wednesday.

“We realize this decision will cause challenges for many of our families. It has, however, become more important for us to take this step in an attempt to diminish the number of people of all ages who get infected,” Veracco wrote in a letter to parents.

Students are being encouraged to take all text books and other school materials home at the end of the day on Friday.