The overwhelming majority of Detroit Public Schools will be closed Monday after the teachers union in the city called for a sickout over concerns about the finances of Michigan’s largest school district.

The following schools will be closed tomorrow, Monday, May 2 due to teacher sickouts… https://t.co/XKdR6SEpEy — DetroitPublicSchools (@Detroitk12) May 2, 2016

In all, 94 out of 97 schools will be closed Monday, according to The Detroit News, which adds:

Union leaders reacted harshly over the weekend after DPS Emergency Manager Steven Rhodes informed them the district won’t be able to make payroll after $48.7 million in emergency state aid runs out on June 30. Rhodes acknowledged in an email to The Detroit News the school district will run out of money then.

The Detroit Federation of Teachers, which represents most of the teachers taking part in Monday’s sickout, said in a series of tweets that its members will rally at 10 a.m. outside the school district’s central administration offices. The News adds: “Public school teacher strikes are illegal in Michigan, and a spate of coordinated sickouts in DPS this winter has caused lawmakers to consider tightening the definition of what constitutes a strike.”

More from the newspaper:

New questions about district’s management under Rhodes’ predecessors came to light recently when the school district disclosed to state officials that up to $30 million in federal aid earmarked for employee pensions was never sent to the state pension fund. The Detroit News reported April 26 that the matter is being investigated in an audit.