The union representing Chicago public school teachers will go on strike on Oct. 11 if it doesn't reach an agreement with the school board by then on a new teachers' contract.

WLS-TV reports that Chicago Teachers Union President Karen Lewis announced the strike date at a new conference. Lewis says the union is continuing to negotiate with district officials.

"We negotiated yesterday, today, and we're negotiating tomorrow. We're going to continue to try and reach an agreement on this contract," Lewis says.

The union is required to provide Chicago Public Schools with a 10-day notice.

Teachers have been working without a contract since June 2015.

The school district released a statement following the union's announcement, saying in part: "What we can all agree on is that teachers deserve a raise, which is why we offered a contract with a healthy raise that was approved by an independent arbitrator. We believe a strike can be averted."

Video from WLS-TV: