Back to school? Chicago calls on teachers to return to classrooms Monday despite no deal with union.

CHICAGO — Chicago Mayor Lori Lightfoot said Sunday evening that the city had not reached an agreement with the Chicago Teachers Union on how and when to reopen schools in the nation's third-largest district.

Approximately 70,000 students were originally expected to return to classes Monday, but Lightfoot said she was directing parents not to bring their students to school until Tuesday. She called on all pre-K through 8 teachers – except those with preapproved accommodations – to return to schools Monday.

"Those who do not report to work, we’re going to have to take action," Lightfoot said.

Chicago Public Schools CEO Dr. Janice Jackson said teachers who do not report Monday will have their access to virtual classrooms cut off at the end of the day.

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More than 3,200 pre-K and special education students returned to classrooms in mid-January for two weeks, but those classes shifted online last week amid an impasse in negotiations between the union and City Hall.

Since Jan. 9, the district has reported 124 actionable cases of COVID-19, according to officials.

"We successfully opened school at the beginning of this year," Jackson said. "We’re now trying to get to a place where we can reopen schools, and those plans are being thwarted for reasons that don’t hold up under scrutiny."

Lightfoot said she had a "cordial and productive" phone call with CTU President Jesse Sharkey on Sunday. She called on the union to return to the bargaining table Sunday night.

"If it takes us staying up all night, let’s get it done, but we need CTU coming back to the table," Lightfoot said. "We are practically begging CTU to come to the table so we can get a deal done."

Lightfoot and union officials said they have reached an agreement on four key issues: health and safety protocols, ventilation, contact tracing and safety committees.

"Those things are a sign of progress," Sharkey said at a virtual press conference Sunday night. "We're stuck on some hard issues."

The outstanding issues include telework accommodations for teachers with immunocompromised household members, a public health metric that would guide school reopening, vaccinations for educators and more, Sharkey said.

"We're not seeing the compromises at the table that we would need," he said.

Union officials did not say if teachers would go on strike if they are locked out of virtual classrooms Monday.

"We hope that we don't get locked out tomorrow," Sharkey said.

This article originally appeared on USA TODAY: Chicago Public Schools reopening uncertain amid union negotiations